How to Make It
Preheat the oven to 350°. Spread the hazelnuts in a pie plate and toast until fragrant and the skins blister, about 12 minutes. Transfer the nuts to a kitchen towel and let cool slightly, then vigorously rub the nuts together to remove the skins. When the hazelnuts are completely cool, pulse them in a food processor until finely ground. Transfer the ground nuts to a bowl.
Add the butter and confectioners' sugar to the food processor and process until light and fluffy. Add the ground hazelnuts, flour, baking powder, cloves and salt and pulse until combined. Add the eggs, brandy and vanilla and process just until a soft dough forms.
Scrape the dough onto a large sheet of plastic wrap. Transfer one-third of the dough to a separate sheet of plastic and roll it into a 6-inch log. Pat the remaining dough into a 6-inch disk. Wrap and refrigerate the dough until firm, at least 2 hours or overnight.
Preheat the oven to 350°. Let the 6-inch disk of dough stand at room temperature for 10 minutes, then set it in a 10-inch fluted tart pan with a removable bottom. Press the dough evenly over the bottom and up the side of the tart pan. In a bowl, mix the jam and cornstarch; spread the jam on the bottom of the tart. Refrigerate until chilled.
Cut the log of dough into 6 slices. On a lightly floured surface, roll each slice into a 1/2-inch-thick strip. Halve 1 strip crosswise. Transfer the strips of dough to a baking sheet and refrigerate until chilled. Lay the strips diagonally across the tart, trimming them to fit; press the ends into the crust rim.
Brush the strips of dough with the beaten egg white. Bake the tart for 40 minutes, or until the crust is browned and the jam is bubbling slightly. Let cool completely, then unmold the tart and slide it onto a plate. Cut into wedges and serve.