Blueberry Crumble Pie with Buttery Oat Topping
Blueberry crumble pie is a juicy, jammy blueberry filling under a crisp, buttery oat topping. It’s the kind of dessert that feels special but comes together with less fuss than a double-crust pie.
The crumble topping gives you all the texture without the stress of a lattice top, and the filling sets up beautifully after cooling.
Why This Blueberry Pie Works
The filling holds its shape when you slice it, thanks to a mix of sugar, cornstarch, and a hit of lemon zest. Nothing gloppy, just clean berry flavor.
The crumble topping gets crisp edges while staying soft underneath, and the oats add a nutty chew that plays off the juicy berries.
I reach for this recipe when I want a pie that tastes like summer but doesn’t demand a hot kitchen for hours. A little patience during the cool-down pays off in the end.
Ingredients
- 1 unbaked 9-inch pie crust: homemade or a good store-bought all-butter crust
- 2/3 cup (135g) granulated sugar: balances the tart berries
- 3 tbsp cornstarch: for a sliceable, not runny, filling
- 1 tbsp lemon zest: brightens the fruit without tasting lemony
- 1/4 tsp fine sea salt: in the filling
- 5 cups (about 25 oz) fresh blueberries: or frozen, see the method
- 1 tsp vanilla extract: rounds out the sweetness
- 3/4 cup (95g) all-purpose flour: for the crumble
- 1/2 cup (45g) old-fashioned rolled oats: adds chew and crunch
- 1/2 cup (105g) packed light brown sugar: for deep caramel notes
- 1/2 tsp ground cinnamon: warm spice that sits in the background
- 6 tbsp (85g) cold unsalted butter, cubed: keeps the crumble tender and crisp
Variations / Substitutions
- Swap the berries: use half blueberries and half raspberries for a tarter, brighter filling. Frozen mixed berries work the same way.
- Make it gluten-free: use a 1:1 gluten-free flour blend in the crumble and certified GF oats. Pick a gluten-free pie crust or make your own.
- Dairy-free option: replace the butter in the crumble with a solid vegan butter stick and use a vegan pie crust. The texture stays just as flaky.
- Add nuts: toss 1/4 cup chopped pecans or almonds into the crumble mixture for extra crunch.
- Change the spice: a pinch of freshly grated nutmeg or ground cardamom works beautifully with blueberries.
Silky Raspberry Custard Pie is another reader favorite dessert worth making next.
How to Make Blueberry Crumble Pie
Step 1: Mix the Crumble Topping
Start by making the oat crumble so it chills while you work on the filling. In a medium bowl, whisk together the 3/4 cup flour, 1/2 cup rolled oats, 1/2 cup brown sugar, 1/2 teaspoon cinnamon, and 1/4 teaspoon salt. Toss in the 6 tablespoons of cold cubed butter and work it with your fingertips until the mixture looks like damp sand with some larger nuggets the size of peas.
You want a mix of small crumbs and bigger clumps, because the little pieces melt into the berries while the bigger chunks stay crunchy on top. Pop the bowl in the fridge so the butter stays cold.
Step 2: Combine the Blueberry Filling
In a large bowl, whisk the 2/3 cup granulated sugar, 3 tablespoons cornstarch, 1 tablespoon lemon zest, and the 1/4 teaspoon salt until no lumps of cornstarch remain. Add the 5 cups of blueberries and 1 teaspoon vanilla extract, then fold gently with a spatula until every berry is glossy and coated.
The cornstarch mixture will look powdery at first, but the moisture from the berries will start to dissolve it. If you’re using frozen berries, don’t thaw them first, just toss them straight in so they release less juice while baking.
Step 3: Roll and Chill the Pie Crust
Roll your pie dough into a 12-inch circle and ease it into a standard 9-inch pie plate. Fold the edge under itself and crimp with your fingers for a tall rim, then put the crust in the fridge for 15 minutes to firm up. You can use a store-bought crust here, just press it in and chill it the same way.
A cold crust hits the oven fat and sets quickly, giving you flaky layers instead of a soggy bottom. This is the moment that decides whether your crust stays crisp.
Step 4: Assemble and Bake the Pie
Preheat the oven to 375°F (190°C) and set a rack in the lower half. Spoon the blueberry filling into the chilled crust, scraping every bit of syrup from the bowl. Scatter the crumble topping evenly over the berries, pressing it down very lightly so it stays on top. Place the pie on a rimmed baking sheet and bake for 50 to 55 minutes, until the filling is bubbling thickly around the edges and the topping is deep golden.
If the crust or topping browns too fast, tent the pie loosely with foil for the last 10 minutes. The bubbling juice should look jammy, not watery, and that’s your sign it’s set.
Step 5: Cool and Slice the Pie
Let the pie cool on a wire rack for at least 3 hours, then slice and serve at room temperature. The filling needs that time to finish setting, so be patient.
When you cut in, the berries will hold together and the crumble will shatter a little in the best way. A long cooling window is the only real trick to clean slices.
Tips for the Best Crumble Pie
- If your blueberries are especially sweet, cut the granulated sugar by a tablespoon so the pie doesn’t taste flat.
- For a deeper flavor, add a teaspoon of almond extract along with the vanilla.
- You can make the crumble topping up to 2 days ahead and keep it in the fridge. Just scatter it on right before baking.
- Using quick oats in the crumble works, but the texture will be less chewy. Stick with old-fashioned rolled oats if you can.
Bake times by pan size:
| Pan type | Bake time at 375°F |
|---|---|
| Standard 9-inch pie plate | 50 to 55 minutes |
| Deep-dish 9-inch pie plate | 60 to 65 minutes |
| 8-inch pie plate | 45 to 50 minutes |
Keeping Leftover Pie Fresh
- Refrigerate: Cover the cooled pie loosely with foil or plastic wrap and keep it in the fridge for up to 4 days. The crumble will soften a bit over time.
- Reheating: Warm individual slices in a 300°F oven for 10 minutes, or in a skillet over low heat, to crisp the topping back up.
What to Serve With Blueberry Pie
A scoop of vanilla ice cream melts into the warm pie and balances the tart berries. For something lighter, a dollop of lightly sweetened whipped cream works beautifully. A bit of crème fraîche or plain Greek yogurt also makes a nice tangy contrast.
Frequently Asked Questions
Do I need to blind bake the crust?
No. The filling starts raw and the long bake time cooks the bottom crust through. Chilling the crust well before filling is enough to keep it crisp.
Why did my crumble sink into the filling?
The crumble can sink if the filling is extra liquidy or if you press the topping down too firmly. Scatter it lightly and don’t pack it, and most of it should stay on top.
How can I make a thicker filling?
If you like a very firm, jammy slice, increase the cornstarch to 4 tablespoons. The filling will set even faster as it cools.
Blueberry Crumble Pie Recipe
Ingredients
Method
- Mix the flour, oats, brown sugar, cinnamon, and salt for the crumble. Cut in the cold butter until the mixture looks like damp sand with pea-sized lumps. Chill.
- Whisk the sugar, cornstarch, lemon zest, and salt. Add the blueberries and vanilla, and fold until the berries are evenly coated.
- Roll the dough into a 12-inch circle, fit it into a 9-inch pie plate, crimp the edges, and refrigerate for 15 minutes.
- Preheat the oven to 375°F (190°C). Spoon the filling into the chilled crust, scatter the crumble on top, and bake on a rimmed baking sheet for 50 to 55 minutes, until bubbling and deep golden.
- Cool on a wire rack for at least 3 hours before slicing. Serve at room temperature.
Notes
