3/4 cup confectioners' sugar, plus about 2 tablespoons for dusting
1/2 cup cornstarch
2 sticks (1/2 pound) unsalted butter, softened
1/2 cup store-bough lemon curd
Preheat the oven to 350°. In a small bowl, stir together the cake flour, 3/4 cup confectioners' sugar and the cornstarch.
In a medium bowl, cream the butter. Stir in the dry ingredients. Spoon the dough into nonstick mini muffin pans with cups about 1 inch deep. Bake for about 20 minutes, or until golden. Let the shortcakes stand for about 10 minutes, then make a 1/2-inch indentation in the center of each with the handle of a wooden spoon. Carefully turn the cakes out onto a rack and let cool completely.
Dust the cakes lightly with confectioners' sugar, then fill each with 1 teaspoon lemon curd.