Pate Sucree: In a mixer fitted with a paddle attachment (or using a hand mixer), mix the flour and sugar. Add the butter and mix until coarse and sandy. In a small bowl, whisk the egg yolk, cream, and vanilla together. Add to the flour mixture and mix at low speed just until combined. Turn out onto a work surface and form into a ball. Roll out dough to fit a 10-inch tart pan with a removable bottom, lightly press it into the pan, and chill for at least 30 minutes.
Filling: Preheat the oven to 375 degrees F.
In a food processor fitted with a metal blade, pulse the hazelnuts and sugar just until sandy. Do not overprocess, or the mixture will become pasty. Add the butter and process just until blended. Add the eggs and process until blended. Scrape down the sides of the bowl, add the vanilla and flour, and process until smooth. Spoon into the unbaked tart shell.
Spread 1 cup of the blueberries in a single layer over the frangipane. Bake until the frangipane is golden brown and puffy and the crust is golden brown, 45 to 50 minutes. Let cool to room temperature.
In a medium saucepan, bring the jam and water to a boil. Immediately turn off the heat. Working quickly, add the remaining blueberries all at once and fold gently with a spatula until evenly coated. Pour into the center of the tart and gently spread over the entire surface. Let cool until set, then remove the sides of the pan. Serve at room temperature.
Recipe courtesy of Gale Gand,