To Prepare Crust: On a floured board, roll the tart dough into an 11-inch circle, 1/8-inch thick. Transfer the dough to a 10-inch tart pan with fluted sides and a removable bottom by rolling the dough around the pin like a carpet and then unrolling it onto the pan. Press the dough into the bottom and sides of the pan, then trim it so it is flush with the top of the pan. Chill the tart shell while you make the topping filling.
1/4 cup Unsalted Butter
3/4 cup Unbleached all-purpose Flour
1/2 cup Granulated Sugar
1/4 teaspoon Kosher Salt
1/2 cup Unsweetened Shredded Dried Coconut
1 teaspoon Pure Vanilla Extract
For the Topping: Melt the butter in a small saucepan over low heat and let it cool. Place the flour, sugar, salt and coconut in a large bowl and whisk together to combine well. Add the vanilla extract to the melted butter, then add the butter mixture to the dry ingredients, stirring with a fork to combine well. Spread the topping in an even layer on a baking sheet lined with parchment or wax paper and chill for 30 minutes, or until firm.
Remove the topping from the refrigerator and place it in the bowl of a food processor. Pulse the mixture several times to make tiny crumbs. Set aside.
1/4 cup Unsalted Butter (softened)
1/2 cup Confectioners Sugar
2 Large Egg Yolks
Freshly grated zest of 1 Lemon
Pinch of Kosher Salt
3/4 cup Unsweetened Shredded Dried Coconut
For the Filling: Place the butter and confectioners' sugar in the bowl of an electric mixer and, using the paddle attachment on medium speed, beat together until smooth and creamy, about 2 minutes. Beat in the egg yolks, one at a time, scraping down the sides. Beat in the lemon zest and salt, followed by the coconut.
Preheat the oven to 375F and position a rack in the center.
About 3 cups Fresh Blueberries
2 tablespoons Freshly Squeezed Lemon Juice
1/4 cup Granulated Sugar
2 teaspoons Cornstarch
For the Assembly: Place the blueberries in a large bowl. Add the lemon juice, sugar, and cornstarch and stir together to combine, thoroughly coating the berries.
Remove the tart shell from the refrigerator and, using a spatula or the back of a spoon, evenly spread the filling in the shell. Top with the blueberries, drizzling any liquid from the bottom of the bowl on top. Evenly cover the surface with the topping crumbs. Bake until the topping is lightly golden and the blueberries are bubbling, 35-45 minutes.
Confectioners' Sugar for dusting (optional)
Serve the tart while still slightly warm, or cool and serve it at room temperature. If desired, garnish with a dusting of confectioners' sugar. Wrapped in plastic, the tart will keep in the refrigerator for a few days.