Grease and flour a 9-inch round cake pan. In a large bowl, mix flour, ground almonds, baking powder, salt, and lemon zest; set aside. With an electric mixer, cream butter and sugar until light, fluffy, and pale in color. Beat in eggs one at a time, following each with a spoonful of the flour mixture to prevent curdling. With a spatula, gently fold in the remaining flour mixture until evenly mixed and smooth (expect the batter to become rather heavy and dough-like). Spread evenly into greased pan.
Preheat oven to 350 F. Bake 40 to 50 minutes, until a toothpick through the middle comes out clean. Let cool 15 minutes, then carefully remove from pan. Cool completely before cutting and serving.
Decorate with candied citrus peel, lemon icing, jam, or fresh berries.
Note: If you can’t find superfine sugar (a.k.a. caster sugar or baker’s sugar — NOT confectioners' or powdered sugar), simply food-process granulated sugar for 30 seconds or so until the granules are visibly smaller.
Per serving: 267 calories, 15 grams fat (8 grams saturated fat), 77 milligrams cholesterol, 189 milligrams sodium, 30 grams total carbohydrate, 1 gram fiber, 5 grams protein.
