The Ultimate Healthy Blueberry Crumble
This easy dessert is secretly healthy enough for breakfast! It’ll keep for at least four days, if not closer to a week or more, if covered with foil or transferred to airtight containers and stored in the refrigerator. (And for a special treat, I highly recommend topping it with a bit of ice cream!)
Ingredients
- ¾ cup (75g) old-fashioned rolled oats (gluten-free if necessary and measured like this)
- ¼ cup (30g) whole wheat flour or millet* flour (measured like this)
- 1 tsp ground cinnamon
- 2 tbsp (30mL) pure maple syrup, room temperature
- 1 ½ tbsp (21g) unsalted butter, melted
- 6 cups (840g) blueberries (see Notes!)
- 3 tbsp (24g) cornstarch (measured like this)
Instructions
- Preheat the oven to 350°F, and coat an 8”-square pan with nonstick cooking spray.
- To prepare the 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, toss the blueberries with the cornstarch in a large bowl until completely coated.
- Transfer the filling to the prepared pan, and sprinkle evenly with the topping. (The topping tends to clump, so break it up into really small pieces!) Bake at 350°F for 45-55 minutes or until the juice is bubbling at the sides of the pan. Cool completely to room temperature; then refrigerate for at least 3 hours before serving to allow the juices to fully thicken.
Notes
IMPORTANT MEASURING NOTES – READ BEFORE BEGINNING: It’s extremely important to measure the flour, oats, and cornstarch correctly, using this method or a kitchen scale. (← That’s the one I own!) Too much flour or too many oats will dry out the streusel – especially the oats! They act like little sponges and soak up lots of moisture from the mixture. If there's too much cornstarch in the filling, it'll remain white and undissolved, and the filling will be too dry.
IMPORTANT STREUSEL NOTES – READ BEFORE BEGINNING: The streusel generally clumps a lot after mixing it together, but if you break it into small bits (aim for the size of miniature chocolate chips — and no larger than the size of peas), I promise there's enough to cover the blueberries in a thin and even layer!
I completely understand that not everyone has the time (or patience!) to break up the streusel in that small of pieces. I also understand that some people prefer a thicker layer of streusel. If you fall into either camp, you can easily double the amount of streusel! Doing so won't affect the baking time, temperature, or anything else.
IMPORTANT BLUEBERRY NOTES – READ BEFORE BEGINNING: Both fresh and frozen blueberries will work. I highly recommend tasting your blueberries first to make sure they're juicy and sweet! If they're not very sweet, then you may want to add sweetener to the filling so your crumble isn't tangy or tart.
If using fresh blueberries, make sure they’re freshly washed! The water clinging to freshly washed blueberries helps dissolve and evenly distribute the cornstarch throughout the filling. Then add 3 tablespoons of water to the blueberry filling — in addition to the water still clinging to the berries after freshly washing them — just before adding the cornstarch. (Without the water, the filling will be dry, and the cornstarch won't fully dissolve.)
If using frozen blueberries, do not thaw them. Toss the frozen blueberries directly with the cornstarch, and bake the crumble for closer to 55-65 minutes instead.
IMPORTANT BAKING NOTE – READ BEFORE BEGINNING: You must let the crumble cool completely to room temperature and chill for 3+ hours before serving in order to let the blueberry juices to fully set. If you'd prefer to serve it warm, see my suggestion below!
OATS ALTERNATIVE: Quick cooking oats (also called "instant" oats or "one minute" oats) may be substituted for the old-fashioned rolled oats. Do not substitute steel-cut oats; they don't soften properly.
FLOUR ALTERNATIVES: White whole wheat flour, whole wheat pastry flour, or all-purpose flour may be substituted for the regular whole wheat flour. Oat flour (gluten-free, if needed) may also be substituted, but be very careful when measuring it because it tends to be more absorbent.
MAPLE SYRUP ALTERNATIVES: Honey or agave may be substituted for the pure maple syrup.
GLUTEN-FREE OPTION: To make the crumble gluten-free, use the millet flour option and certified gluten-free old-fashioned rolled oats or certified gluten-free quick cooking oats.
Almost any other gluten-free flour will work in place of the millet flour — except for coconut flour. Do not substitute coconut flour because it makes the topping too dry and crumbly.
DAIRY-FREE + VEGAN OPTION: For a vegan version, substitute stick-style vegan butter (I like this one and this one) for the best results. Coconut oil will also work, but the flavor and texture of the topping will be slightly different.
HOW TO STORE: Store this blueberry crumble in the refrigerator, either fully covered with foil or in an airtight container. Leftovers should keep for at least four days, if not closer to a week or more!
SERVING WARM: If you prefer to enjoy your crumble warm, then reheat individual portions once it has chilled in the refrigerator.
{gluten-free, egg-free, dairy-free option, vegan option, clean eating, low fat, 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.