Junior's Sponge Cake Crust

1. Preheat the oven to 350°F and generously butter the bottom and side of a 9- or 8-inch springform pan (preferably a nonstick one). Wrap the outside with aluminum foil, covering the bottom and extending it all the way up the side.

2. In a small bowl, sift the flour, baking powder, and salt together.

3. In a large bowl, using an electric mixer, beat the egg yolks on high for 3 minutes. With the mixer running, slowly add 2 tablespoons of the sugar and continue beating until thick light yellow ribbons form in the bowl, about 5 minutes more. Beat in the extracts.

4. Sift the flour mixture over the batter and stir it in by hand, just until there are no remaining white flecks. Blend in the melted butter.

5. In another clean bowl, using clean, dry beaters, beat the egg whites and cream of tartar together on high until frothy. Gradually add the remaining sugar and continue beating until stiff peaks form (the whites will stand up and look glossy, not dry). Fold about one-third of the whites into the batter, then the remaining whites. Don't worry if you still see a few white specks, as they'll disappear during baking.

6. Gently spread the batter over the bottom of the prepared pan and bake just until set and golden (not wet or sticky), about 10 minutes. Touch the cake gently in the center. If it springs back, it's done. Watch carefully and don't let the top brown. Leave the crust in the pan and place on a wire rack to cool. Leave the oven on while you prepare the batter for the cheesecake.