Recipe

Easy Blueberry Crumble

Jammy blueberry filling, crisp oat topping, and just enough lemon to make the berries taste louder.

By Matt Campbell

•

4.8

A golden-brown blueberry crumble in a white ceramic baking dish with bubbling purple-blue edges and a crisp oat topping, set on a light kitchen counter

Blueberry crumble is the dessert I make when I want something that feels like I tried, without actually trying that hard. You get the whole warm, jammy fruit situation, plus a topping that bakes into crunchy little buttery peaks. It is equal parts cozy and bright, which is exactly the energy I want from dessert.

This version is built for real life. Fresh berries, frozen berries, whatever you have. A little lemon to keep the filling from tasting flat. A pinch of salt in the crumble because sweet needs a good wingman. And yes, we are aiming for crisp edges and bubbly corners because those are the best bites.

A bowl of fresh blueberries next to small bowls of rolled oats, flour, brown sugar, and cubes of butter on a bright kitchen counter

Why It Works

Jammy, not soupy filling: Cornstarch thickens the berries so you get spoonable sauce instead of blueberry juice everywhere. (And if your berries are extra juicy, you can bump it up a bit.)
Crunch that stays crunchy: The topping uses a balance of flour and oats, plus cold butter, so it bakes up crisp and nubbly.
Bright flavor: Lemon zest and juice wake up blueberries, especially if you are using frozen fruit.
Flexible and forgiving: Works in an 8x8 dish, a similar-size casserole, or even individual ramekins if you want to feel fancy.

Pairs Well With

Storage Tips

Fridge: Cover the baking dish or transfer leftovers to an airtight container. Refrigerate for up to 4 days.

Reheat: For the crispiest topping, reheat in a 350°F oven for 10 to 15 minutes. Microwave works in a pinch, but the crumble will soften (still delicious, just more cozy than crisp).

Freeze: Freeze baked crumble, tightly wrapped, for up to 2 months. Thaw overnight in the fridge, then re-crisp in a 350°F oven until warmed through.

A glass meal prep container filled with leftover blueberry crumble, showing a layer of purple filling and crisp oat topping, sitting on a kitchen counter

Common Questions

Can I use frozen blueberries?

Yes. Use them straight from frozen. Do not thaw, or the filling can get watery. You may need an extra 5 to 10 minutes of bake time because the berries start colder.

Why is my crumble topping not crispy?

Usually one of three things: the butter was too warm, the topping was packed down too firmly, or the crumble needed a few more minutes in the oven. Keep the butter cold, sprinkle the topping loosely, and bake until you see deep golden bits across the surface.

How do I keep the filling from being runny?

Cornstarch needs heat and a little time to thicken. Make sure the filling is actively bubbling, not just at the edges but with a few bubbles in the center too, then let the crumble cool for at least 20 minutes before serving. Hot crumble is lava-soupy. Warm crumble is perfect.

Do I need more cornstarch for frozen berries?

Sometimes. If your frozen berries are extra juicy, bump the cornstarch up to 1 tablespoon for a thicker, more jammy filling.

Can I make it gluten-free?

Yes. Swap the flour for a 1:1 gluten-free baking blend, and use certified gluten-free oats.

Can I make it ahead?

You can mix the crumble topping up to 3 days ahead and keep it in the fridge. You can also assemble the whole dish and refrigerate it for a few hours before baking. Bake straight from the fridge, adding a few extra minutes if needed.

Any easy variations?

Absolutely. Swap in mixed berries, add a handful of chopped pecans or walnuts to the topping, or shave a tablespoon or two off the sugar if your berries are very sweet.

Matt Campbell

I have always had a huge passion for the culinary arts, people, working as a team, and so on. I wanted to pursue my love for cooking initially at Virginia Commonwealth University with a culinary arts degree; however, I instead decided to apply myself and acquire more practical skills. My end goal is to eventually open my own restaurant or similar establishment.

Kitchen Essentials

8x8-inch baking dish or similar 2-quart (8x8-inch) dish
Mixing bowls (1 medium, 1 large)
Microplane or fine grater (for lemon zest)
Measuring cups and spoons
Fork or pastry cutter (for cutting in butter)
Sheet pan (optional, to catch drips)

I started making crumble when I realized pie was mostly a patience tax. I love pie, but I do not always love the whole chill, roll, pray, patch, chill again routine on a random weeknight. Crumble is the friend who shows up in sweatpants and still looks good. Blueberry is my go-to because it tastes like summer, but it also plays nice in the dead of winter with a bag of frozen berries and a little extra lemon.

Easy Blueberry Crumble

(4.8 Reviews)

Prep Time 15 minutes

Cook Time 40 minutes

Total Time 55 minutes

Servings 6

Ingredients

Blueberry filling

4 cups blueberries (about 18 to 20 oz), fresh or frozen
1/3 cup granulated sugar
1 tbsp lemon zest (from 1 large lemon)
2 tbsp lemon juice
2 tsp cornstarch (use 1 tbsp for extra-juicy or frozen berries if you like it thicker)
1 tsp vanilla extract
1/4 tsp kosher salt

Crumble topping

3/4 cup old-fashioned rolled oats
1/2 cup all-purpose flour
1/2 cup packed light brown sugar
1/2 tsp ground cinnamon
1/4 tsp kosher salt
6 tbsp cold unsalted butter, cut into small cubes

Optional for serving: vanilla ice cream, whipped cream, or plain Greek yogurt if you want breakfast energy.

Instructions

Heat the oven. Preheat to 350°F. Set a rack in the middle of the oven. Lightly butter an 8x8-inch baking dish. If your dish tends to bubble over, set it on a sheet pan.
Mix the blueberry filling. In a large bowl, add blueberries, granulated sugar, lemon zest, lemon juice, cornstarch, vanilla, and salt. Toss until the berries look glossy and the cornstarch disappears.
Make the crumble topping. In a medium bowl, mix oats, flour, brown sugar, cinnamon, and salt. Add the cold butter cubes and cut them in with a fork or pastry cutter until you have pea-size pieces and some sandy bits. If you squeeze a handful, it should clump.
Assemble. Pour the blueberry mixture into the baking dish and spread it into an even layer. Sprinkle the crumble topping evenly over the berries. Do not pack it down. Loose topping equals more crisp edges.
Bake. Bake for 35 to 45 minutes, until the filling is bubbling and you see some bubbling in the center, and the topping is golden brown with deeper golden spots. If the topping browns too fast, loosely tent with foil for the last 10 minutes.
Cool, then scoop. Let cool for 20 to 30 minutes to thicken up. Serve warm with ice cream if that is your thing.