Easy Blueberry Crumble (Fresh or Frozen Blueberries)
Blueberry crumble is the fastest fruit dessert there is — toss berries with sugar and cornstarch, top with a buttery oat crumble, and bake. It works with fresh or frozen blueberries (no thawing), needs no mixer, and is done in under an hour. The cornstarch keeps those juicy berries from turning the whole thing soupy.
The Quick Version
- Fresh or frozen blueberries — don’t thaw frozen, just add extra cornstarch.
- Cornstarch is non-negotiable — blueberries are very juicy.
- Cool 15–20 minutes — it goes from soupy to spoonable as it sets.
- 10 minutes of work, one bowl for the topping.
How to make it
- Heat oven to 350°F (175°C). Toss 5 cups blueberries with ⅓ cup sugar, 1½ tbsp cornstarch and 1 tbsp lemon juice; spread in a buttered 9-inch dish.
- Stir 1 cup oats, ¾ cup flour, ½ cup brown sugar, ½ cup melted butter and salt into clumps.
- Scatter the topping over the berries.
- Bake 38–45 minutes until golden and bubbling thickly. Cool 15–20 minutes.
Foolproof tip: wait for the berries to bubble thickly at the edges, not just simmer — that’s how you know the cornstarch has activated and the filling will set.
Frequently asked questions
Can I use frozen blueberries in a crumble?
Yes — no thawing needed. Add an extra ½ tablespoon of cornstarch for the extra juice and a few more minutes of baking.
Why is my blueberry crumble watery?
Blueberries are very juicy — cornstarch thickens the filling, and cooling 15–20 minutes firms it from soupy to spoonable.
Can I make it ahead?
Yes — assemble and refrigerate up to a day before baking, or bake fully and reheat at 325°F.
Easy Blueberry Crumble
Ingredients
Instructions
- Heat oven to 350F (175C). Toss the blueberries with granulated sugar, cornstarch and lemon juice, then spread in a buttered 9-inch baking dish.
- Stir the oats, flour, brown sugar, melted butter and salt into clumps.
- Scatter the topping over the berries.
- Bake 38-45 minutes, until the topping is golden and the berries bubble thickly at the edges. Cool 15-20 minutes so the filling sets.
More easy fruit desserts
One of our easy fruit desserts. For a cold berry treat, see no-bake summer desserts, or browse all baking ideas.
