Blueberry Crisp with Lemon & Almonds

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Inside: The difference between a blueberry crisp that’s one note or one with dimension? The secret’s a double dose of lemon zest–in the topping and the filling, plenty of crunch from sliced almonds and oats–plus the right way to thicken the juices without lumps or gumminess.

Craving a warm blueberry crisp with a scoop of vanilla melting in? This blueberry crisp recipe is foolproof, using fresh or frozen berries, and it delivers a deep, gooey blueberry flavor, elevated with a touch of citrus and a contrast of crunchy, buttery oat-and-almond crumble. It’s a warm, family-style dessert you can make in about an hour.

A serving of blueberry crisp with a scoop of vanilla ice cream.

As a self-proclaimed lazy baker, I gravitate toward desserts that are simple to assemble, don’t require a pastry degree, and deliver results I’m happy to share with both family and friends. Fruit crisps, cobblers and crumbles are always reliable. From my tropical Mango Crisp, classic Cherry Peach Crisp, fall-favorite Apple Cranberry Crisp and this Blueberry Crisp (which has been updated since its original publication).

I’ve always said that summer fruit is the best, and blueberries hit their peak from June through August; plump and sweet from the heat, which is when I make this crisp most. But if you’re reading this in the dead of January, craving something warm and fruity, don’t wait for July — a bag of frozen blueberries works just as well here, no need to thaw first.

My husband is the bellwether for when they need to be used — he tops his morning yogurt with them but only when they’re at peak freshness. The second they start to soften, he lets me know “we” (meaning me) need to do something with them. This warm crisp is always the answer.

For this recipe I add a good dose of fresh lemon zest and juice to both the filling and topping, which brightens the berries without overpowering them — a citrusy tang that plays beautifully against all that natural blueberry sweetness.

For the classic oat crisp topping, I skip the brown sugar you’ll find in most versions and use granulated instead for a more blonde-golden finish. Sliced almonds and oats give the crisp topping a satisfying crunch.

Why this blueberry crisp recipe works:

Juicy blueberries–make an oozy filling. Cornstarch sets the berry filling clear and glossy rather than cloudy and pasty, so the fruit still looks (and tastes) like fruit, not paste; but there’s a method for adding it.
Cubed chunks of butter — I don’t melt the butter for this topping. Rubbing cold butter into the dry ingredients by hand leaves coarse, uneven crumbs that bake into a craggier, crunchier topping we prefer rather than a uniform, cakey one.
Rolled or quick oats, never instant — Instant oats break down more quickly and will disappear into the topping as it bakes. Rolled or even quick-cooking oats hold their shape for a crispier texture.
Lemon zest in both layers — Most recipes add lemon to the filling only. Zesting it into the topping too means the citrus note carries all the way through the dish, not just in the fruit.
Granulated sugar, not brown — I find brown sugar’s molasses notes tend to compete with the lemon; granulated lets the citrus shine through.

Ingredients you’ll need:

Fresh Blueberries–actually, you can use fresh or frozen berries for equally delicious results. If using frozen, don’t thaw first; use them straight from the freezer.
Lemon–in this blueberry crisp recipe, you’ll need the zest and juice of one lemon. I use the zest in both the fruit filling and crumble topping. A lemon should yield 2-3 teaspoons of lemon zest and at least one tablespoon lemon juice (if not two). Look for lemons with a smooth, firm skin, not the ones that have dried out – they won’t have the abundant lemony flavor.
Granulated Sugar–to lightly sweeten the berries and the crisp.
Cornstarch–when blended with sugar, acts as a thickener for the fruit (without any lumps).
All Purpose Flour–the basis of the topping, it coats the butter to create an irresistibly crumbly layer.
Salt–sweet things need a bit of salt to counter-balance and bring more dimension to any sweet-baked recipe. See it at work in my Salted Tahini Chocolate Chip Cookies.
Chilled Unsalted Butter–Instead of using room temperature butter, I prefer cold chunks to provide a shaggy-looking topping with larger crumbles.
Rolled or Quick-Cooking Oats–for texture and chew. Most fruit crisps include an oatmeal element, but don’t substitute instant or steel-cut varieties. They won’t work here.
Sliced Almonds–optional, but good. Adds a great crunch to the finished fruit dessert.

Step-by-step instructions:

Combining the dry ingredients for the crisp topping.

Combine the flour, sugar, salt and zest of half a lemon in a medium bowl and whisk togegther.

Adding cubed butter and after the butter has been worked through.

2. Add the cold, cubed butter and work it into the flour mixture with a fork or your clean hands (my favorite method) until it’s got a crumbly, sandy appearance.

3. Add the oatmeal and almonds and toss to combine. Set aside.

4. Remove any stems from the fruit, then transfer to a colander or large sieve and rinse the blueberries with cold running water; drain well and transfer to a large bowl.

5. Add the remaining lemon zest, then juice the lemon and add it to the fruit; stir to evenly coat the berries.

6. Combine the sugar and cornstarch and whisk together until blended, then sprinkle it over the fruit. Toss blueberries with a rubber spatula to fold them in until the fruit is coated with the sugar mixture.

Fill the baking dish and top with oatmeal crumble.

7. Transfer the berry mixture to an oven-proof casserole dish and sprinkle the lemon almond crisp topping evenly over the fruit.

8. Bake at 375°F for 30-35 minutes until the blueberries and bubbling and the crisp topping is golden brown.

Pro-Tips:

Taste the berries first–summer fruit is usually sweeter than shoulder season, and depending on their tartness, you may want to adjust the sugar.
Zest before you juice — Zest the lemon first, then juice it. Once you’ve squeezed a lemon, zesting what’s left is a lot harder. Ask me how I know.
Keep the butter cold — If your kitchen’s warm (hello, Florida summers), pop the flour mixture in the freezer for 10 minutes before cutting in the butter. Cold butter is what gives you those craggy, crunchy clumps and crumbs.
Using frozen berries? Add a little extra cornstarch — Frozen blueberries release more liquid as they bake. An extra half tablespoon of cornstarch keeps the filling from going soupy. Ensure the fruit in the blueberry mixture is evenly coated without overstirring.
Don’t overwork the berries — Fold the sugar and cornstarch in just until coated. Overmixing bruises the berries and pulls out more juice than you want.
Topping browning too fast? — If it’s golden before the filling’s bubbling, tent it loosely with foil for the last 10 minutes so the fruit catches up without burning the topping.

Mistakes to avoid

Melting the butter instead of cutting it in cold — Melted butter gives you a denser, cakier topping. Cold butter, worked in by hand, is what creates those craggy crumbs.
Don’t use flour in place of cornstarch–yes, it can be used as a thickener, but it will cloud the fruit filling.
Serving it straight out of the oven — The filling is molten and needs 10-15 minutes to rest. It also thickens slightly as it cools, so cutting in too early gives you a runnier bite than you want.
Using a dish that’s too shallow — or too deep 5 cups of berries need room to bubble without spilling over. Too shallow, and the bubbling filling can overflow; too deep, and the dessert looks paltry.
Avoid a mess in the oven–place your baking dish on a foil-lined sheet pan to catch drips.
Don’t use steel-cut oats–they will break your teeth if they’re not cooked first–and cooked, they won’t give you the texture you want.

Scooping blueberry crisp from the casserole dish.

Swaps and Substitutions:

Fruit — Swap in raspberries, blackberries, or chopped peaches, or use a mixture of fruit. If adding peaches, cut them into small bite-sized chunks, slightly larger than the berries.
Fresh vs. frozen — Either works. Rinse and pick over fresh berries; don’t thaw frozen ones, just toss them in straight from the freezer (see the Pro Tips for adjusting cornstarch).
Berries not quite perfect? It’s ok; slightly soft or bruised fruit works great in a crumble; it’s going to cook down anyway! Whenever our berries are one or two days past their prime, I make this.
All-purpose flour — Sub a 1:1 gluten-free flour blend in the topping. Just make sure your oats are certified gluten-free too, since regular oats are often cross-contaminated.
Butter — A plant-based butter or margarine works fine if you need dairy-free; just make sure it’s a stick style, not a spread, so you get the same crumbly texture.
Sliced almonds — Swap for chopped pecans, walnuts or other nuts; leave them out entirely for a nut-free version. You’ll still get crunch from the oats.
Granulated sugar — Coconut sugar can sub in a pinch, but it’ll mute the lemon a bit the same way brown sugar does — worth knowing before you swap.
Lemon — Lime works as a substitute if that’s what you have on hand; it shifts the flavor slightly more floral and a bit less sharp, but still bright.
Spices–if you like a little spice, add ¼ teaspoon of ground ginger, cardamom or ground cinnamon to the topping mixture. These spices play especially nicely in the crumble.
Blueberry crisp in ramekins–assemble the crisps in individual ½-¾ cup ramekins for individual desserts; perfect for dinner parties and company.

FAQs

Can I use frozen blueberries?

Yes — no need to thaw first. Add a little extra cornstarch since frozen berries release more liquid as they bake.

Can I double this recipe for a 9×13 dish?

Yes, double all the ingredients. Expect a slightly longer bake — start checking at 40 minutes and pull it once the filling is bubbling throughout, not just at the edges.

Why is my topping soggy instead of crisp?

Usually one of two culprits: melted butter instead of cold, or pulling it from the oven before the filling’s bubbling all the way through. Bubbling means the moisture’s cooking off and thickening the juices–another visual cue that the topping is baked.

What do I serve with it?

I recommend a puff of freshly whipped cream (or a squirt of Reddiwip; it’s fancy, but not too fancy) or a scoop of vanilla ice cream.

An overhead shot of the blueberry crisp with a scoop of vanilla melting into it.

Make ahead:

You can make the topping up to 2 days ahead of time and keep it refrigerated until you’re ready to bake.

Storage:

The blueberry crisp keeps well in the refrigerator for up to 4 days, covered with plastic wrap or in an airtight container, but it’s best within the first 2 days.

Reheating:

Reheat in a 350° oven, uncovered, for about 15 minutes until warmed through.
The microwave works in a pinch but softens the topping.

Freezing:

I don’t recommend freezing this dish because the topping loses its crunch and the flavors can get muddled.
For the best texture, freeze the unbaked components separately and bake fresh.

More blueberry desserts to make:

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