Caramelized Nut Tart

To make the pastry, in a food processor fitted with the metal blade, combine the flour, sugar and salt and pulse just to mix. Add the butter and pulse until the mixture resembles coarse meal. With the motor running, add water as needed for the mixture to come together in a rough mass.

Gather the dough into a ball and flatten into a 6-inch disk. Cover with pplastic wrap and refrigerate for 30 minutes.

Gently press the pastry into the bottom and sides of a 9 1/2-inch tart pan with a removable bottom, forming an even layer on the bottom and building up the sides slightly. Place the shell in the freezer for 30 minutes.

Preheat an oven to 400°F.

Line the pastry with aluminum foil and fill with pie weights. Bake for 10 minutes. Remove the weights and foil and reduce the heat to 375°F. Continue to bake until lightly golden, 15 to 20 minutes more. Transfer to a wire rack and let cool. Leave the oven set at 375°F.

To make the filling, fill a small saucepan half full of water, add the baking soda and bring to a boil. Add the hazelnuts and boil for 30 seconds. Drain, immediately place in a kitchen towel and rub to remove the skins. Chop the hazelnuts coarsely. Spread the hazelnuts, almonds, walnuts and pecans on a baking sheet and bake until the almonds are lightly golden, 3 to 5 minutes. Remove from the oven and set aside.

Position a rack in the upper part of the oven and increase the heat to 400°F.

In a saucepan over medium-high heat, combine the cream, sugar and vanilla extract. Bring to a boil and boil until slightly thickened, about 3 minutes. Remove from the heat and stir in all the nuts. Let stand for 15 minutes.

Pour the filling into the prebaked tart shell and place on a baking sheet. Bake until the top is a combination of creamy white and russet-caramel in color and is dotted all over with small holes, 30 to 35 minutes. Transferthe pan to a rack and cool for 15 minutes, then remove the pan sides and slide the tart onto a serving plate. Serve at room temperature.