Blueberry Hazelnut Pie

Take 80 grams (⅔ cup) of the toasted, skinned hazelnuts, pulse in a food processor until finely ground, taking care not to overprocess into hazelnut butter. Add 190 grams (1.5 cups) all-purpose flour, 50 grams (¼ cup) granulated sugar, and ½ teaspoon fine sea salt, pulsing 2-3 times to evenly combine. Add 113 grams (8 tablespoons) of cold, cubed unsalted butter, pulsing until the mixture resembles coarse crumbs with pea-sized butter bits remaining. Drizzle in ice cold water 1 tablespoon at a time, pulsing between additions, until the dough just clumps together when squeezed. Form the dough into a 1-inch thick disk, wrap tightly in plastic wrap, and chill in the refrigerator for 30 minutes.

Preheat your oven to 190°C (375°F). Remove the chilled dough from the refrigerator and let it rest at room temperature for 5 minutes to soften slightly, so it does not crack when rolled. Roll the dough on a lightly floured work surface to a 12-inch circle, about 3mm (⅛-inch) thick. Gently lay the rolled dough into a 9-inch standard pie dish, pressing it firmly against the bottom and up the sides of the dish. Trim excess dough overhang to 1 inch, fold the overhang under itself, and crimp the edges decoratively. Prick the bottom of the crust all over with a fork, line the crust with parchment paper, and fill with ceramic pie weights or dried beans to prevent puffing.

Place the weighted, lined crust on the middle oven rack and bake for 15 minutes at 190°C (375°F). Carefully lift out the parchment paper and pie weights, then return the crust to the oven to bake for 5 more minutes, until the bottom is pale golden and set to the touch. Transfer the par-baked crust to a wire rack to cool slightly, and reduce the oven temperature to 180°C (350°F).

In a large mixing bowl, combine the rinsed and thoroughly dried fresh blueberries, remaining 80 grams (⅓ cup) granulated sugar, cornstarch, lemon zest, fresh lemon juice, vanilla extract, and ¼ teaspoon fine sea salt. Toss gently with a silicone spatula until all blueberries are evenly coated in the sugar-cornstarch mixture, then let sit for 5 minutes to allow the berries to release a small amount of juice.

Chop the remaining 40 grams (⅓ cup) of toasted, skinned hazelnuts into coarse, uneven pieces. In a small mixing bowl, combine the remaining 30 grams (¼ cup) all-purpose flour, chopped hazelnuts, remaining 57 grams (4 tablespoons) cold cubed unsalted butter, and a small pinch of fine sea salt. Use your fingertips to rub the butter into the flour until the mixture forms coarse, pea-sized crumbly clumps for the streusel topping.

Pour the prepared blueberry filling evenly into the par-baked crust, spreading it into a smooth, even layer. Sprinkle the hazelnut streusel topping evenly over the surface of the blueberries. Bake the pie on the middle oven rack at 180°C (350°F) for 45 to 50 minutes, until the filling is thickly bubbling at the edges and the streusel topping is deep golden brown. If the crimped crust edges begin to brown too quickly, wrap them in a thin ring of aluminum foil after 25 minutes of baking to prevent burning. Let the baked pie cool completely on a wire rack for 2 full hours before slicing, to allow the filling to set properly.