1. Dough: Whisk together flour, sugar, baking powder, and salt. Cut in butter with a pastry cutter or rub it in with your fingers until small bits remain. Stir in egg, and mix until a dough forms. Fit dough into a buttered 9-inch pie plate using plastic wrap or wet fingers. Spread 1/4 cup plus 2 tablespoons preserves on bottom of tart shell. Refrigerate until firm, about 20 minutes.

2. Filling: Preheat oven to 350 degrees. Beat together butter, sugar, and extracts with a mixer on medium-high speed until light and fluffy, about 3 minutes. Add eggs, 1 at a time, beating well after each addition. Stir in nuts. Spread filling over preserves in tart shell.

3. Bake tart until crust is deep golden brown and filling is set, 40 to 45 minutes. Transfer to a wire rack, and let cool completely, about 1 hour. Spread with remaining 1/4 cup preserves. Tart can be stored at room temperature, tented with foil, up to 1 day. Or, after tart cools, store it at room temperature, wrapped in plastic, then foil, up to 3 days; spread with preserves before serving.