Add the flour, sugar, and salt to a large bowl, and whisk to combine.
1 ¼ cups all-purpose flour, 1 ½ teaspoons granulated sugar, ½ teaspoon salt
Work the cold butter into the flour mixture with a pastry cutter, two forks, or your fingertips until the butter is broken down into pea-sized pieces and coarse crumbs.
½ cup unsalted butter
Drizzle in the ice water, 1 tablespoon at a time, and gently mix until the dough just starts to hold together when pressed. Add a little more water only if needed.
¼ cup ice water
Form the dough into a flat disk, wrap it tightly in plastic wrap, and chill for at least 1 hour.
To make the crumb topping
While the dough chills, prepare the crumb topping. Add the flour, brown sugar, and cold butter to a food processor, and pulse until the mixture forms moist crumbs with no dry flour left. Refrigerate until ready to use.
1 cup all-purpose flour, ½ cup light brown sugar, ½ cup unsalted butter
Prep the crust
When the dough is chilled, roll it out on a lightly floured surface into a 12-inch circle. Place it in a lightly greased 9-inch pie plate, press it gently into the bottom and sides, then trim and crimp the edges.
Use a fork to prick holes in the bottom and sides of the crust. Return the pie plate to the refrigerator while you make the filling.
To make the filling
Add the blueberries, sugar, ¼ cup water, lemon juice, lemon extract (if using), and lemon zest to a large saucepan over medium heat. Stir often and cook until the berries begin to release their juices and the mixture starts to bubble.
4 cups blueberries, ¾ cup granulated sugar, ¼ cup water, ¼ cup lemon juice, 1 tablespoon lemon zest, ½ teaspoon lemon extract
In a small bowl, whisk the remaining ¼ cup water with the cornstarch until smooth.
¼ cup water, ¼ cup cornstarch
Stir the cornstarch mixture into the blueberries. Continue cooking and stirring until the filling thickens, then cook for 1 to 2 more minutes.
Remove the pan from the heat, and let the filling cool for 10 to 15 minutes.
Preheat the oven to 400°F, and line a baking sheet with parchment paper or foil.
Assemble and bake
Pour the blueberry filling into the chilled pie crust.
Break the crumb topping into small pieces, about dime-size or smaller, and scatter it over the filling.
Set the pie on the prepared baking sheet, and bake for 40 to 50 minutes. The pie is ready when the topping is golden and the filling is bubbling up through the crumbs.
If the crust starts browning too fast, tent the edges loosely with foil.
Cool the pie at room temperature for 1 to 2 hours, then refrigerate for at least 3 to 4 hours before slicing. Overnight is even better.
Notes
Pie dish size: I use a standard 9-inch pie dish for this recipe, and the filling fits with just enough space. It can bubble over a bit, so don’t skip the parchment- or foil-lined baking sheet underneath.
Store-bought crust: If you’re using a store-bought pie crust to save time, I recommend using a deep-dish crust. Regular frozen pie shells may not leave enough room for the blueberry filling and crumb topping.
Crumb topping alternative: You can also make a lattice top or use a double crust instead of the crumb topping.
Keep everything chilled: Keep the pie dough and crumb topping cold. Both contain butter, and chilling helps the crust hold its shape and keeps the topping from spreading too much in the oven.
Use small pieces for the topping: Don’t use large pieces of crumb topping. The bigger pieces are heavy, may not bake evenly, and can sink into the blueberry filling.
Save some topping for later: You don’t have to use all of the crumb topping. Use about half to three-quarters if you want cleaner slices, then save the rest for muffins or another small dessert.
How to know when it's done: The pie is done when the filling bubbles through the topping, not just when the crust looks brown. That bubbling is what helps the cornstarch-thickened filling set.
Clean-ish slices: This pie slices best after chilling overnight. Even then, the topping may crack or break a little when cut. It’s meant to be tasty, not win a beauty pageant.
Storage: Store leftover pie covered in the refrigerator for up to 4 days. The crumb topping will soften as it sits, but it still tastes great. Freezing is fine for up to 2 months; the texture will change a bit.
Nutrition Facts
Lemon Blueberry Pie
Serving Size
1 slice
Amount per Serving
Calories
518
% Daily Value*
Fat
24
g
37
%
Saturated Fat
15
g
75
%
Trans Fat
1
g
Polyunsaturated Fat
1
g
Monounsaturated Fat
6
g
Cholesterol
61
mg
20
%
Sodium
335
mg
14
%
Potassium
129
mg
4
%
Carbohydrates
75
g
25
%
Fiber
3
g
12
%
Sugar
41
g
46
%
Protein
4
g
8
%
Vitamin A
750
IU
15
%
Vitamin C
11
mg
13
%
Calcium
30
mg
3
%
Iron
2
mg
11
%
* Percent Daily Values are based on a 2000 calorie diet.