Healthy Practically Flourless Peanut Butter Cookie Bars with Chocolate Frosting
Yields: 16 cookie bars
These cookie bars are perfect for anyone who loves buckeyes, Reese’s 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.
  1. Preheat the oven to 325°F, and coat an 8”-square pan with nonstick cooking spray.
  2. 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 vanilla stevia. Add in the oat flour mixture, stirring just until incorporated.
  3. 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.
  4. While the cookie bars bake, prepare the frosting. Beat the Greek yogurt, instant pudding mix, cocoa powder, and vanilla 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.
  5. 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: I used this oat flour! (This is the gluten-free version.) You can also make your own. I show you how here!

Be very careful when measuring the oat flour! Use this method or a kitchen scale. (← That’s the one I own and love!) Too much oat flour will make your cookie bars turn out dry or cakey, rather than soft and chewy.

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

For a non-oat-flour gluten-free option, use store-bought gluten-free flour blends (like this one!).

This is my homemade creamy peanut butter recipe! You just need 5 minutes and a blender 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.

Any milk may be substituted for the unsweetened cashew milk.

I highly recommend using the vanilla stevia! It's one of my favorite ingredients, and you'll use it in all of these recipes of mine too. I buy mine online here because that's the best price I've found.

You cannot substitute additional honey for the vanilla stevia because the cookie bars require a precise balance of wet and dry ingredients. However, you may substitute ¾ cup (144g) coconut sugar (or brown sugar or granulated sugar, if you aren’t concerned about keeping these cookies clean eating friendly) for both the honey and stevia, but the cookies will appear “speckled” if using coconut sugar because it doesn’t dissolve as well.

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

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

This is the instant pudding mix that I use. You just need the dry instant pudding mix—don’t prepare it according to the package directions! You may omit it, but you’ll need to increase the cocoa powder and vanilla stevia (and just mix the ingredients together until 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 of mine instead (no pudding mix required!)

For a vegan option, substitute pure maple syrup or agave for the honey in the cookie bars. Then use this chocolate frosting recipe of mine instead, and substitute your preferred non-dairy milk.

{gluten-free, clean eating, low fat, vegan option}
Recipe by Amy's Healthy Baking at