This tart has a soft cookie-like crust, and is a great showcase for sweet, fresh blueberries. I only make it in the summer, when blueberries are in season.
For the crust:
16 tablespoons (2 sticks) unsalted butter, melted
1/3 cup sugar
1.5 teaspoons vanilla extract
1/4 teaspoon salt
2 cups all-purpose flour
1/2 teaspoon baking powder
For the filling:
5 to 6 cups fresh blueberries
3/4 cups (5.25 ounces) sugar
1/3 cup water
2 tablespoons unbleached all-purpose flour
1/8 teaspoon salt
grated zest of 1 small lemon
To make the crust: Melt the butter (I use microwave) and then combine butter, sugar, vanilla, and salt, in a bowl. Mix the flour and baking powder together thoroughly, add to the butter mixture, and mix just until well blended. If the dough seems too soft, let it stand for a few minutes to firm up. It will be less firm than cookie dough.
Press the dough over the bottom and up the sides of a 11-inch tart pan to make a thin, even layer making sure to press the dough uniformly around the edges of the pan to avoid extra-thick edges. (The crust can be prepared up to 2 days in advance. Wrap well and refrigerate until ready to use. Bring to room temperature before baking). Place tart pan on a baking sheet and bake for 22 – 25 minutes, until the crust is fully golden brown all over. If the crust puffs up during baking, gently press it down with the back of a fork and prick it a few times. Set the baked crust aside while you prepare the filling.
Combine 2.5 cups of blueberries with the sugar, water, flour, salt, and lemon zest in a medium saucepan and bring to a simmer over medium heat, stirring frequently. Then simmer, stirring, until the filling is thickened and translucent, about 3 more minutes.
Spread the remaining 3 cups of uncooked blueberries in the tart crust. Spoon the hot blueberry mixture into the crust, covering the raw blueberries evenly. Spoon enough liquid into the tart so that it just comes up to the edge of the crust. Discard excess liquid, if there is any. Let cool, then refrigerate for at least 2 hours, until the filling is set.
Serve the tart cold. Remove the sides of the pan and transfer the tart to a serving platter. The tart keeps well, covered, in the refrigerator for up to 2 days.