Why You’ll Love This Recipe

I love this crumble because it celebrates peak-season berries in the simplest form. It comes together in under 10 minutes of prep, bakes into bubbling perfection, and the oat topping adds that perfect crunch. It’s practically foolproof and feels special with minimal effort

ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

Berry filling

2 cups mixed berries (raspberries, blueberries, strawberries)
1 Tbsp lemon juice
2 Tbsp granulated sugar (or maple syrup)
1 tsp vanilla extract

Oat crumble

1 cup rolled oats
½ cup all-purpose flour (or gluten-free flour)
⅓ cup brown sugar
¼ tsp ground cinnamon
¼ tsp salt

directions

Preheat oven to 350 °F (175 °C).
In a bowl, toss berries, lemon juice, sugar (or syrup), and vanilla until evenly coated. Spread into an 8×8″ or similar baking dish
In another bowl, stir together oats, flour, brown sugar, cinnamon, and salt.
Add cold butter (about ½ stick), then use fingers or a pastry cutter to form a crumbly mixture with pea-sized clusters.
Evenly sprinkle the oat crumble over the berry layer.
Bake uncovered for 40–50 minutes, until the berries are bubbling around the edges and the topping is golden and crisp
Let rest for about 10 minutes so the juices settle before serving.

Servings and timing

Servings: Makes about 8 servings
Prep time: ~10 minutes
Bake time: ~40–50 minutes
Rest time: ~10 minutes
Total time: ~1 hour

Variations

Nutty crunch: Stir chopped pecans or walnuts into the crumble for extra texture
Maple twist: Substitute maple syrup for sugar in the berry mixture for warm sweetness.
Gluten-free: Use gluten-free oats and flour—still deliciously crisp
Mixed fruit: Add diced peaches or apples alongside berries for varied flavor.
Lemon zest: Stir in zest to the filling for bright citrus notes .

storage/reheating

I store leftovers covered in the fridge for up to 5 days
To reheat, I warm it in a 350 °F oven for ~10 minutes to revive the crispier topping, then serve with ice cream or whipped cream.

FAQs

Can I use frozen berries?

Yes—no need to thaw. Bake time stays the same, though filling may be juicier .

My topping feels dry—what can I do?

Drizzle a bit of melted butter over it mid-bake and stir gently, then bake a few more minutes

Can I prepare ahead?

Absolutely—I assemble it, refrigerate unbaked for up to 12 hours, then bake straight from the fridge adding a few extra minutes .

Can I freeze it?

Yes—freeze baked or unbaked for up to 2–3 months. Bake from frozen, adding about 10 minutes to baking time .

How do I prevent the berries from being runny?

Tossing them with a bit of flour or cornstarch helps thicken excess juice as it bakes .

Conclusion

This Triple Berry Oat Crumble is one of my all-time favorites—simple, bright, and texturally satisfying. It’s the perfect make-ahead dessert or breakfast treat that feels comforting yet fresh. Serve it warm with ice cream or yogurt, and enjoy that magical, seasonal flavor in every bite.