Step 1Heat the oven to 350 degrees. Butter a 13 1/2 -by-4-inch rectangular tart pan with a removable bottom and set aside. Toast the hazelnuts 10 to 12 minutes in a shallow baking pan, stirring the nuts or shaking the pan a few times for even toasting. Let the nuts cool completely in the pan. Place one-third cup of the hazelnuts in a food processor and pulse to a fine grind for the crust; do not over-process or the nuts will become pasty. Coarsely chop the remaining hazelnuts to sprinkle over the top of the tart. Set aside.
Step 2In a mixing bowl, combine the ground hazelnuts, flour, sugar and salt. Add the butter and, with a fork or pastry cutter, work it into the flour mixture just until it resembles small peas. Drizzle 2 tablespoons ice water over the top of the dough and toss with a fork just until the dough forms a ball; if it is still a bit crumbly, add up to 1 additional tablespoon ice water. The butter will not be completely incorporated; there will be streaks of butter remaining in the dough.
Step 3Shape the dough into a flat 3-by-8-inch rectangle and cover with plastic wrap. Chill the dough about 30 minutes.
Step 4Remove the dough and roll it into a rectangle about 6 inches by 15 inches and one-fourth-inch thick to fit the tart pan. Carefully lift the dough into the pan, pressing it onto the bottom and sides. Trim the dough so that it's even with the edges of the pan. Chill 30 minutes before baking.
Step 5Line the tart dough in the pan with aluminum foil and fill with pie weights. Bake 15 minutes, then remove the foil and pie weights. Continue to bake the tart 10 to 15 minutes until golden around the edges. Remove the tart from the oven to a wire rack to cool completely.
Step 6Combine the cranberries, brown sugar, kosher salt, grated orange zest, orange juice, and figs in a medium bowl. Spoon the filling evenly into the tart crust still in the tart pan; the filling will mound a bit in the center. Put the tart on a baking sheet and bake. After 25 minutes check the tart for browning. If the top looks like it's browning too quickly, tent the top with aluminum foil. Bake a total of 55 minutes to 1 hour, until the cranberries pop and the sugar caramelizes. Remove to a wire rack to cool. Sprinkle the remaining chopped hazelnuts over the top.
Step 7Whip the cream to soft peaks, then beat in the powdered sugar, Cognac and vanilla extract. Serve the whipped cream with the tart.