Healthy Blueberry Apple Crisp (Crumble)
I love this light and simple dessert! A layer of spiced oat crumble covers the juicy berries and tender melt-in-your-mouth apples underneath. An irresistible combination of crunchy topping, soft fruit, and naturally sweet flavor, this summery dessert is simple to make any day of the week. Whether you call it a crisp or a crumble, it’s the perfect treat for fruit fans — with or without a little ice cream on top! Leftovers will keep for at least three days (if not longer!) if stored in the refrigerator in the original baking pan covered with foil or inside of an airtight container.
Ingredients
FOR THE STREUSEL
- ¾ cup (75g) instant oats (gluten-free if necessary and measured like this)
- ¼ cup (30g) whole wheat flour or gluten-free* flour (measured like this)
- 1 tsp ground cinnamon
- 2 tbsp (30mL) pure maple syrup, room temperature
- 1 ½ tbsp (21g) unsalted butter or stick-style vegan butter, melted (see Notes!)
FOR THE FILLING
- 4 cups (510g) ¼" slices Fuji apple, cut into thirds (about 3 large or 4 medium – and see Notes!)
- 2 cups (280g) fresh blueberries, freshly washed (see Notes!)
- 2 tbsp (16g) cornstarch
- 1 tsp ground cinnamon
Instructions
- Preheat the oven to 350°F, and coat an 8”-square pan OR 9”-round pan with nonstick cooking spray.
- To prepare the streusel topping, whisk together the oats, flour, and cinnamon in a small bowl. Make a well in the center. Pour in the maple syrup and melted butter. Stir until fully incorporated.
- To prepare the filling, thoroughly toss the apples and blueberries with the cornstarch and cinnamon in a large bowl until evenly coated with cinnamon and the cornstarch has completely dissolved (with zero visible white specks – and the apples often stick together, so pry them apart when needed!).
- Transfer the filling to the prepared pan, and gently press down with a spatula or the back of a spoon until the top is even and flat. Sprinkle evenly with the streusel. (The streusel typically clumps a LOT, so break it up into really small, itty bitty pieces as you go!) Very gently press the streusel into the filling with your hands. Bake at 350°F for 65-75 minutes or until juice bubbles around the edges and the apples are very fork tender. Cool completely to room temperature; then refrigerate for at least 3 hours before serving to allow the juice to fully thicken.
Notes
IMPORTANT MEASURING NOTE – READ BEFORE BEGINNING: It’s very important to measure the oats and flour correctly, using this method or a kitchen scale. (← That’s the one I own.) Too much of either ingredient will dry out the streusel topping. If this happens to you, add additional maple syrup or milk (any type!) ½ teaspoon at a time or until you can fully incorporate all of the oats and flour.
IMPORTANT PAN SIZE NOTES – READ BEFORE BEGINNING: An 8”-square pan and 9”-round pan have very similar surface areas (64 in2 and 63.6 in2, respectively!), so your fruit crisp will turn out the same, regardless of which pan you use.
Pan dimensions are measured along their top rims, not their bottom sides. If using the round pan option, measure directly across its middle (aka the diameter) from one lip of the opening to the other. If using a square pan, measure across its top edge, not the bottom. 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. Use a 9”-round pie plate or cake pan instead!
Do not substitute a 9”-square pan. Because it has a larger surface area (81 in2), there won’t be enough streusel to cover the top, and your fruit crisp will bake differently as well.
IMPORTANT COOLING NOTE – READ BEFORE BEGINNING: You must let this crisp cool completely to room temperature and chill for 3+ hours (closer to 8 hours is even better!) for the cornstarch to fully thicken the juices. If you try to serve your fruit crisp sooner, the filling will still be runny. (See the “To serve warm” note below if you’d like to serve your fruit crisp warm instead!)
IMPORTANT APPLE NOTES – READ BEFORE BEGINNING: It’s important to slice the apples into ¼”-thick slices to help them bake evenly and soften completely. I know it takes a little extra time and effort, but I promise it’s worth it!
If you leave the apple slices whole, or in halves instead of thirds, you end up with big gaps in the filling. If you make your apples thicker, closer to ½”- to ¾”-thick chunks, they take longer to cook and don’t always soften fully. The goal with the thin, smaller apple chunks is to make them closer in size to the blueberries, which ensures all of the fruit bakes at around the same rate. (See the “Prep the fruit” header in the “How to Make the Best Healthy Blueberry Apple Crisp” section in my blog post above for more information.)
I personally love Fuji apples because they’re naturally sweet and hold their shape while baking without turning soggy, mealy, or disintegrating. Gala and Braeburn apples would work as well. If you prefer a tarter flavor, then substitute up to 1 cup of diced Granny Smiths for the equivalent amount of Fuji apple, but I’d recommend against more than that since you aren’t adding any sweetener to the filling.
IMPORTANT BLUEBERRY NOTES – READ BEFORE BEGINNING: Make sure they’re freshly washed! The water clinging to freshly washed blueberries helps dissolve and evenly distribute the cornstarch throughout the filling.
I highly recommend using fresh blueberries, if at all possible. When you mix fresh and frozen fruit, the filling can bake unevenly.
IMPORTANT TOPPING NOTE – READ BEFORE BEGINNING: The oat streusel tends to clump — a lot! — so break it up into itty bitty pieces before you sprinkle it over the apples. The pieces should be between the size of miniature chocolate chips and peas. (I promise there’s enough streusel to cover the fruit if you do this!)
If you prefer a thicker layer of streusel, then double the ingredients for the streusel.
OATS NOTES + ALTERNATIVE: Instant oats are also called quick-cooking or one-minute oats. They only include one ingredient: oats! Old-fashioned rolled oats (gluten-free, if necessary!) may be substituted for the instant oats. I slightly prefer instant oats because they’re smaller and thinner than old-fashioned rolled oats, which helps prevent the streusel topping from clumping as much. Do not substitute steel-cut oats.
FLOUR ALTERNATIVES: White whole wheat flour, whole wheat pastry flour, all-purpose flour, or oat flour (gluten free, if needed) may be substituted for the regular whole wheat flour.
CINNAMON NOTE: I highly recommend Saigon cinnamon! It’s richer and sweeter compared to regular cinnamon. I buy mine online here (← it’s really affordable!), and it’s practically the only kind I use in my baking now.
SWEETENER ALTERNATIVES: Honey or agave may be substituted for the pure maple syrup.
CORNSTARCH NOTE: The cornstarch thickens the juice that the fruit releases while baking. I haven’t tried substituting anything for it, and I don’t recommend omitting it. The filling will be very liquidy and soup-like without it.
GLUTEN-FREE OPTION: To make the crumble gluten-free, use certified gluten-free instant oats or certified gluten-free old-fashioned rolled oats. For the flour, almost any gluten-free flour will work — except for coconut flour. Do NOT substitute coconut flour! It’ll make the topping too dry and almost sandy. My favorite gluten-free flours are millet flour, brown rice flour, almond flour, and oat flour.
DAIRY-FREE + VEGAN OPTION: Use stick-style vegan butter (I like this one and this one) in place of the unsalted butter for the best results. Coconut oil may be substituted, but the taste and texture will be slightly different.
TO SERVE WARM: You must let this blueberry apple crisp cool completely to room temperature AND set for 3+ hours in the refrigerator before serving. (If you have time, chilling for 8+ hours is even better!) This allows the cornstarch to fully thicken the juices that the fruit releases while baking. If you’d prefer to serve your crumble warm, then reheat it after the cornstarch has worked its magic! As the easiest option, I typically reheat individual slices in the microwave.
HOW TO STORE: Store leftover fruit crisp in the refrigerator, either still in the pan and covered with foil or inside of an airtight container. It should last for at least three days, if not longer.
{gluten-free, egg-free, dairy-free option, vegan option, clean eating, low fat, lower sugar, low calorie}
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.