The Ultimate Guide to Homemade Blueberry Crumble

A buttery oat topping brings out the best in seasonal berries for an effortless dessert.

By Medha deb

Created on Sep 17, 2025

A buttery oat topping brings out the best in seasonal berries for an effortless dessert.

If you’re searching for the quintessential summer dessert, look no further than the homemade blueberry crumble. Bursting with sweet-tart blueberries, topped with a crunchy, buttery oat crumble, and easily made in advance, this classic treat is a favorite at family gatherings, potlucks, or any celebration of the season’s freshest fruit.

What Makes Blueberry Crumble So Special?

Blueberry crumble is beloved for being simple, delicious, and incredibly versatile. The dessert features a thick layer of juicy blueberries enhanced by lemon juice and vanilla beneath a crisp, golden topping made from oats, flour, sugar, cinnamon, and melted butter. Unlike pies or cobblers, a crumble is quick to assemble and lets the fruit shine while ensuring maximum crunch in every bite. With the aroma of baked berries and brown sugar wafting through your kitchen, it’s easy to see why this dessert is such a crowd-pleaser.

Ingredients: Building Blocks of Flavor

Blueberry crumble is all about fresh, straightforward pantry staples enhanced by beautiful berries. Here’s a breakdown of what goes into making this dessert:

Crumble Topping

1 1/2 cups rolled or quick-cooking oats – Adds crunch and a hearty texture that pairs well with fruit fillings.
3/4 cup all-purpose flour – Provides structure to the crumble, helping it bake up perfectly crisp.
3/4 cup brown sugar – Sweetens the topping, also lending a caramel-like depth from the molasses in the sugar.
1 tsp. ground cinnamon – For warm, aromatic spice.
1/2 tsp. kosher salt – Brightens and balances the sweetness.
3/4 cup melted butter, plus more for the pan – The key to a golden, clumpy, irresistible crumble.

Blueberry Filling

2/3 cup granulated sugar – Enhances the natural sweetness of the blueberries.
1/4 cup cornstarch – Thickens the berry juices as they bubble in the oven, preventing a runny crumble.
8 cups fresh blueberries – The star of the show; peak-season blueberries deliver the best flavor and juiciness.
1 tsp. vanilla extract – Adds subtle floral depth.
2 tbsp. lemon juice – Brightens the filling and balances sweetness.

Optional for Serving: Whipped cream or classic vanilla ice cream

Step-by-Step: How to Make Blueberry Crumble

Preheat the oven: Set your oven to 350°F (175°C) for a perfectly baked, golden topping.
Prepare the crumble topping:
- In a medium bowl, stir together oats, flour, brown sugar, cinnamon, and salt.
- Pour in the melted butter, mixing until all dry ingredients are evenly moistened and small clumps form.
- Chill the topping in the refrigerator for 30 minutes or freeze for 10 minutes. This helps the butter solidify slightly, yielding a crunchier topping after baking.
Mix the blueberry filling:
- In a large bowl, combine granulated sugar and cornstarch.
- Add in blueberries, vanilla extract, and lemon juice. Stir gently but thoroughly to coat the berries with the sugar-starch mixture.
Assemble:
- Generously butter a 3-quart casserole dish or deep baking dish.
- Spoon the blueberry filling into the dish, spreading it in an even layer.
- Sprinkle the chilled crumble topping evenly across the surface.
Bake:
- Place in the preheated oven and bake for about 45 minutes, until the edges are bubbly and the topping turns golden brown.
- Let the crumble rest for 15 minutes before serving. This allows the juices to thicken and makes for easier serving.
Serve:
- Spoon the warm crumble into bowls, topping each with whipped cream or a generous scoop of vanilla ice cream for a classic touch.

Expert Tips and Tricks

Make-Ahead Topping: The oat crumble topping can be made a day ahead and kept refrigerated, or even frozen for up to three months. Assemble the dessert fresh for the best texture.
Frozen Blueberries: If fresh berries aren’t available, frozen blueberries work perfectly. Thaw them first, then drain away excess liquid or blot with a paper towel to prevent too much moisture in your crumble.
Baking Dish: Use a deep baking dish or casserole to avoid boil-over as the berries release their juices and bubble during baking.
Serving Suggestions: Blueberry crumble is at its best warm, but leftovers are excellent at room temperature or chilled. For extra indulgence, serve with vanilla ice cream, whipped cream, or even lemon sorbet for a refreshing twist.

Blueberry Basics: Using Your Blueberry Haul

Blueberries are a standout ingredient for more than just crumbles. In peak season, this fruit is bursting with flavor and versatility.

Snacking: Enjoy blueberries fresh from the container as a healthy snack.
Breakfasts: Add them to pancakes, muffins, smoothies, or scones.
Beverages: Try them in homemade lemonades or limeades—blueberry-basil limeade is especially refreshing.
Other Desserts: Mix blueberries into cakes, cobblers, or even pies (see table below for differences between common blueberry desserts).

Blueberry Desserts at a Glance

Dessert	Main Feature	Topping/Base	Best Served
Blueberry Crumble	Thick layer of berries, crisp oat streusel	Oat, flour, brown sugar topping	Warm with ice cream
Blueberry Cobbler	Berries under biscuit-style crust	Drop biscuit or dough	Warm; sometimes with cream
Blueberry Pie	Encased blueberry filling	Pastry crust, often lattice	At room temp or chilled
Blueberry Crumb Cake	Soft cake with scattered berries	Crumb/streusel topping	Warm or room temp

Storage, Reheating, and Make-Ahead Advice

Blueberry crumble is easy to store and reheat, making it a convenient dessert for busy schedules or meal planning.

Counter: Covered tightly, crumble can be left at room temperature for 2–3 days.
Refrigerator: Store, covered, for up to 4–5 days. Bring to room temperature or warm in the oven before serving.
Freezing: The unbaked crumble topping freezes well for up to 3 months. You can also freeze fully baked, cooled crumble in portions—defrost and reheat as needed.
Reheating: To serve warm, place the baking dish or an individual serving in a 350°F oven for 10–20 minutes, or until the filling is hot and bubbly and the topping is crisp again.

Frequently Asked Questions

What is blueberry crumble made of?

The topping is a blend of oats, flour, brown sugar, cinnamon, salt, and melted butter. The filling combines blueberries, lemon juice, vanilla, sugar, and cornstarch for thickening.

Can I use frozen blueberries in crumble?

Yes. Thaw frozen blueberries, then drain or blot away excess liquid before using. This prevents the filling from becoming too watery while baking.

How should I store blueberry crumble?

After baking, keep blueberry crumble covered on the counter for 2–3 days or in the refrigerator for up to 4–5 days.

How do I reheat blueberry crumble?

Reheat in a 350°F oven for 10–20 minutes, or until hot and bubbly. Individual servings can also be warmed in the microwave for a short time, though the topping will stay crispier when reheated in the oven.

Can I make blueberry crumble ahead?

Yes. The crumble topping can be prepped in advance and stored in the fridge or freezer. Assemble just before baking for the freshest results.

Pro Tips for Blueberry Crumble Success

Flavor Boosters: Add a hint of orange zest, a pinch of ground ginger, or swap some of the blueberries for blackberries or raspberries for a flavor twist.
Texture Variations: For extra crunch, toss in chopped nuts like pecans or walnuts to the crumble topping.
Serving Flair: Offer lemon zest or mint leaves as garnish on top of whipped cream or ice cream for a pretty finish.
Batch Baking: Double the recipe to feed a crowd or bake in individual ramekins for single servings.

About the Author

Erin Merhar is the Food Director at ThePioneerWoman.com, overseeing test kitchen operations and all things culinary. A trained professional chef and food stylist, she brings passion and know-how to every recipe she creates, especially when it comes to time-honored desserts like blueberry crumble.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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