Healthy Peanut Butter Cookie Bars with Chocolate Frosting

 
For most Christmases while I was in middle and high school, my grandma drove across town to our house before 7 am. As a family of morning people, we gathered around the brightly lit tree in our family room and started opening presents first thing, often before the sun rose.  

Grandma always tucked three large tins underneath the tree as soon as she arrived, along with a few smaller gift bags and envelopes. My brother and I waited impatiently until we could crack open the tin with our names on it… Because we already knew what hid inside!
 

 
Five dozen extremely soft homemade sugar cookies with coarse red and green sanding sugar sprinkled on top, all tied up in festive plastic bags. Then Grandma baked homemade crunchy toffee cookies for Dad’s tin, and she lovingly hand rolled and dipped homemade buckeyes for Mom’s. (Mom was — and still is — a huge chocoholic… And I inherited my chocolate obsession from her!)

With dozens of sweets in each of our tins, we always shared with everyone else. We had more than enough to go around! Yet somehow, those buckeyes (spheres of sweet peanut butter candy dipped in chocolate!) always seemed to disappear first.

While walking down the candy and nut aisle at the grocery store last week to pick up more cashews, I noticed a display of Reese’s peanut butter cups. My mind ended up wandering to memories of Grandma’s homemade buckeyes because they shared the same flavors… And I started craving them before I even walked out of the grocery store!
 

 
Yet because I felt too lazy to roll and dip dozens of candies, I baked a batch of these healthy peanut butter cookie bars with chocolate frosting instead. They have the same flavors, but they’re much less time-consuming to make!

Unlike Grandma’s buckeyes, these also contain no butter, oil, or refined sugar… With less than 30 minutes of active prep! Sweet, simple, and oh so satisfying. Sounds like total bliss to me!
 

HOW TO MAKE HEALTHY PEANUT BUTTER COOKIE BARS WITH CHOCOLATE FROSTING

So let’s go over how to make these healthy peanut butter cookie bars — and the healthy chocolate frosting too!

I actually debated whether to call them flourless or practically flourless for a long time… Because you’re starting with oat flour (like this!). Oat flour is just finely ground oats. But somehow, “powdered oats” doesn’t quite have the same ring to it as “oat flour.” 😉

So what do you think? Flourless peanut butter cookie bars? Or practically flourless peanut butter cookie bars? Either way, they’re SO good! Soft, chewy, delicious cookie bar heaven.

Tip: To make these peanut butter cookie bars gluten-free, use gluten-free oat flour! I also have an easy DIY oat flour tutorial, if you’d like to make your own oat flour.
 

 
Next comes the homemade creamy peanut butter! This is my homemade PB recipe. It just takes 5 minutes to make it, and it yields the best creamy peanut butter. It’s much cheaper than many store-bought peanut butter jars too!

If you opt for store-bought creamy peanut butter, then use the natural drippy-style kind. The only ingredients on the label should be “peanuts” and “salt.” (A little oil is okay too!)

Tip: Don’t substitute crunchy peanut butter! Those “crunchy” bits take up space in your measuring spoons, so you end up with less of the creamy part… And that throws off the ratio of wet and dry ingredients. For the best results, stick with creamy peanut butter!

You’ll skip the eggs in these healthy peanut butter cookie bars. Yes, no eggs! Instead, you’ll mix in some unsweetened cashew milk to bind everything together. This is my favorite cashew milk! It’s so thick and creamy, similar in texture to light cream, but it’s only 25 calories per cup. I use it in many of my baking recipes!

Tip: Just about any milk will work, so feel free to use what’s already in your fridge!
 

 
To sweeten your peanut butter cookie bars, you’ll use a combination of honey (like this) and liquid stevia (this kind). There’s a reason behind this! If you tried to sweeten the cookie bars just with honey, that would add way too much liquid to the cookie dough… And they’d end up with a bready, cakey, almost muffin-like consistency.

So that’s why you’ll use half honey and half liquid stevia! Stevia is a plant-based, no-calorie sweetener that contains nothing refined or artificial (aka it’s clean eating friendly). It’s also highly concentrated — and that’s key to achieving the best chewy texture! You just need 1 teaspoon, which is the sweetness equivalent of almost ½ cup of honey or sugar, and this small amount doesn’t add nearly as much liquid to the dough. That definitely helps keep these peanut butter bars chewy, like regular cookies… And low calorie too!

This is the liquid stevia that I use because I love its sweet flavor and don’t notice any strange aftertaste like with some other stevia products. Although you can find it at most health-oriented grocery stores, I buy mine online here because that’s the best price I’ve found. (And you’ll use it in all of these recipes of mine too!)

Hint: Many stevia brands and products have different sweetness levels, so they’re not necessarily 1-for-1 substitutes for each other! To make sure your healthy peanut butter cookie bars turn out with the right taste and texture, I highly recommend using the same one that I do.
 

 
Once you’ve pressed your cookie dough in the pan (remember to use a spatula!) and popped that in the oven, it’s time to mix up the healthy chocolate frosting. I couldn’t decide which part I liked better… The chewy peanut butter cookie bars or this frosting!

It’s super simple to make! Just add the chocolate frosting ingredients to a bowl, beat with a hand-held mixer for 2 minutes, and then refrigerate for 2 hours. That’s it!

Greek yogurt is the first frosting ingredient. I love how it yields an incredibly smooth and creamy frosting consistency without any butter or powdered sugar! I’ve used Greek yogurt to make many different frosting flavors over the years, and I’ve found that certain brands perform better than others. This one is my current favorite because it’s super thick and has a milder flavor.

Next comes unsweetened cocoa powder. It’s important to use regular unsweetened cocoa powder in this frosting, rather than Dutched or special dark cocoa powder. That’s because regular cocoa powder has a stronger flavor, so it’ll shine through and yield a better taste!
 

 
Although a little surprising for frosting, you’ll also need chocolate instant pudding mix. The chocolate instant pudding mix thickens your yogurt-based frosting and gives it a normal buttercream-like consistency. (You can omit it if you’d like, but you’ll need to add extra unsweetened cocoa powder and sweetener — and only mix the ingredients together by hand until they’re just incorporated!)

Finally, you’ll use a bit more liquid stevia as the frosting’s sweetener. That’s right — no powdered sugar involved! To make things easy, I use the same liquid stevia in both the cookie bars and frosting.

Still with me? We’re almost done! All that’s left to do is spread your chocolate frosting across the top of your cooled peanut butter cookie bars… Cut them into squares…
 

 
And enjoy! And when you make your own, remember to snap a picture and share it on Instagram using #amyshealthybaking and tagging @amyshealthybaking IN the photo itself! (That guarantees I’ll see your picture! 🙂 ) I’d love to see your healthy peanut butter cookie bars with chocolate frosting!

Healthy Peanut Butter Cookie Bars with Chocolate Frosting

© Amy's Healthy Baking

Yields: 16 cookie bars

These cookie bars are perfect for anyone who loves buckeyes, chocolate peanut butter cups, or any other chocolate + peanut butter treats. The peanut butter cookie bars are soft and chewy, and the rich chocolate frosting makes them even more irresistible! Leftovers will keep for at least four days if stored in an airtight container in the refrigerator.

5 from 1 vote

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Ingredients 

FOR THE COOKIE BARS

• 1 ½ cups (180g) oat flour (gluten-free if necessary and measured like this)
• ¼ tsp baking soda
• ¼ tsp salt
• 5 tbsp (80g) homemade creamy peanut butter
• 6 tbsp (90mL) unsweetened cashew milk
• 1 ½ tsp vanilla extract
• ¼ cup (60mL) honey
• 1 tsp liquid stevia (see Notes!)

FOR THE FROSTING

• 1 cup (240g) plain nonfat Greek yogurt
• 1 serving (11g) sugar-free, fat-free chocolate instant pudding mix
• 2 tbsp (10g) unsweetened cocoa powder (measured like this)
• ⅜ tsp liquid stevia (or adjusted to taste)

Instructions

• Preheat the oven to 325°F, and coat an 8”-square pan with nonstick cooking spray.
• To prepare the cookie bars, whisk together the oat flour, baking soda, and salt in a medium bowl. In a separate bowl, whisk together peanut butter, cashew milk, and vanilla extract. Stir in the honey and liquid stevia. Add in the oat flour mixture, stirring just until incorporated.
• Using a spatula, gently press the cookie dough into the prepared pan in a thin, even layer. Bake at 325°F for 10-12 minutes or until the center feels firm to the touch. Cool completely to room temperature in the pan.
• While the cookie bars bake, prepare the frosting. Beat the Greek yogurt, instant pudding mix, cocoa powder, and liquid stevia together using an electric hand mixer or stand mixer for 2 minutes. Cover the bowl with foil, and chill for at least 2 hours.
• Once the cookie bars are completely cool, spread the frosting across the top. (I highly recommend an offset spatula like this to do so!) Slice them into 16 square bars.

Notes

IMPORTANT MEASURING NOTE – READ BEFORE BEGINNING: It's extremely important to measure the oat flour correctly, using this method or a kitchen scale. (← That’s the one I own!) Too much oat flour will make your cookie bars turn out dry or cakey, rather than soft and chewy.

 

IMPORTANT PAN SIZE NOTE – READ BEFORE BEGINNING: Pan dimensions are measured along their top rims, not their bottom sides. Some square baking dishes have sloped sides, so they’re 9” across the top and closer to 8” across the bottom. If that’s true for your baking dish, it’s actually a 9”-square pan and too big for this recipe. Because it has a larger surface area (81 in²), your bars would turn out really thin, barely hold together, and be prone to overbaking.

 

IMPORTANT BAKING NOTE – READ BEFORE BEGINNING: Do not over-bake these bars! They’re ready to come out of the oven when the edges feel firm but the center still look slightly glossy and underdone. The heat from the pan will continue to cook the center all the way through while you let the bars cool to room temperature and set.

 

OAT FLOUR NOTES + ALTERNATIVES: I love this oat flour. (This is the gluten-free version.) You can also make your own. I show you how here!

 

White whole wheat flour, whole wheat pastry flour, regular whole wheat flour, or all-purpose flour may be substituted for oat flour.

 

PEANUT BUTTER NOTES: This is my homemade creamy peanut butter recipe. You just need 5 minutes to make it! If using store-bought creamy peanut butter, make sure it’s the natural drippy-style kind that only contains peanuts and salt. Do not substitute crunchy peanut butter.

 

MILK ALTERNATIVES: Any milk may be substituted for the unsweetened cashew milk.

 

HONEY ALTERNATIVES: Pure maple syrup or agave may be substituted for the honey.

 

STEVIA NOTES + ALTERNATIVES: Many stevia brands and products have different sweetness levels, so they’re not necessarily 1-for-1 substitutes for each other. For the best results, use the same liquid stevia that I do. I buy it online here (← that’s the best price I’ve found!), and you’ll use it in all of these recipes of mine too. (It's one of my favorite ingredients!)

 

In the cookie bars, you cannot substitute additional honey for the liquid stevia because the cookie bars require a precise balance of wet and dry ingredients. However, you may substitute ¾ cup (144g) coconut sugar, brown sugar, or granulated sugar for both the honey AND stevia. (The cookie bars will appear “speckled” if using coconut sugar because it doesn’t dissolve quite as well.)

 

If you prefer not to use the liquid stevia in the frosting, then substitute 1 teaspoon of this powdered stevia OR 2-3 tablespoons of Truvia or powdered sugar.

 

INSTANT PUDDING MIX NOTES + FROSTING ALTERNATIVES: This is the instant pudding mix that I use. You just need 1 serving of the dry instant pudding mix — do not prepare it according to the package directions!

 

You may omit it for a "clean eating" version, but you’ll need to increase the cocoa powder and liquid stevia (and only mix the ingredients together until just incorporated — not for 2 full minutes!). Without the instant pudding mix, the frosting will be a bit runny and may slightly drip down the sides of your cookie bars.

 

You can also use this chocolate frosting recipe (option #3) of mine instead — no pudding mix required!

 

GLUTEN-FREE OPTION: Use certified gluten-free oat flour. For a non-oat-flour gluten-free option, many store-bought gluten-free flour blends will work. (I like this one.)

 

EGG-FREE, DAIRY-FREE + VEGAN OPTION: Substitute pure maple syrup or agave for the honey in the cookie bars. Then use this chocolate frosting recipe (option #3) of mine instead.

 

HOW TO STORE: Store leftover cookie bars in an airtight container in the refrigerator. They should last for at least four days.

 

{gluten-free, egg-free, low fat, clean eating option, dairy-free option, vegan option}

DID YOU MAKE THIS RECIPE?I'd love to hear what you think of it in a comment below! If you take a picture, tag @amys.healthy.baking on Instagram or use the hashtag #amyshealthybaking.

View Nutrition Information + Weight Watchers Points
 
 
You may also like Amy’s other recipes…
♡  Healthy Peanut Butter Cookies (practically flourless, like these cookie bars!)
♡  Healthy Extra Fudgy Brownies (practically flourless too!)
♡  Healthy Chocolate Chip Cookie Dough Bites (practically flourless too!)
♡  Healthy Triple Chocolate Mug Cake (practically flourless too!)
♡  Healthy Buckeyes
♡  10-Minute Healthy Buckeye Fudge
♡  …and the rest of Amy’s healthy dessert bar recipes!