Ingredients

• 1.5 cups All-purpose flour
• 0.5 cup Unsalted butter
• 0.25 cup Granulated sugar
• 1 Large egg yolk
• 1 tablespoon Cold water
• 0.25 teaspoon Salt
• 4 cups Fresh blueberries
• 0.25 cup Granulated sugar
• 1 tablespoon Cornstarch
• 1 teaspoon Lemon zest
• 1 tablespoon Unsalted butter
• 1 Large egg white
• 2 tablespoons Apricot jam

Instructions

1. 1

   Prepare the Pâte Sablée: In a large bowl, whisk together the flour, 1/4 cup granulated sugar, and salt. Add the cold, diced unsalted butter and cut it into the flour mixture using a pastry blender or your fingertips until the mixture resembles coarse crumbs. Add the egg yolk and 1 tablespoon of cold water, mixing until just combined. If the dough is too dry, add the remaining tablespoon of water, a teaspoon at a time. Form into a disc, wrap in plastic, and refrigerate for at least 30 minutes.

2. 2

   Preheat Oven & Roll Dough: Preheat your oven to 375°F (190°C). On a lightly floured surface, roll out the chilled dough into a 12-inch circle. Carefully transfer the dough into a 9-inch tart pan with a removable bottom. Press it gently into the bottom and up the sides. Trim any excess dough from the edges. Prick the bottom of the pastry shell with a fork several times. If desired, brush the bottom and sides with a lightly beaten egg white (from the unused egg white) to prevent sogginess.

3. 3

   Prepare the Blueberry Filling: In a separate medium bowl, gently combine the fresh blueberries with 1/4 cup granulated sugar, cornstarch, and lemon zest (if using). The cornstarch helps to thicken the juices released by the blueberries during baking.

4. 4

   Fill and Bake: Pour the blueberry mixture evenly into the prepared tart shell. Dot the top of the blueberries with the small pieces of unsalted butter.

5. 5

   Bake the Tart: Place the tart on a baking sheet and bake in the preheated oven for 35-40 minutes, or until the pastry crust is golden brown and the blueberries are bubbling and tender.

6. 6

   Cool and Glaze (Optional): Remove the tart from the oven and let it cool completely on a wire rack before removing it from the pan. For an extra shine and touch of sweetness, gently warm the apricot jam in a small saucepan or microwave until fluid, then strain it through a fine-mesh sieve. Brush the top of the cooled blueberries with the warmed apricot jam.

7. 7

   Serve: Slice and serve the Tarte aux Myrtilles warm or at room temperature, perhaps with a dollop of crème fraîche or vanilla ice cream.