1. Preheat oven to 350 degrees. Cut a 9-inch round of parchment or waxed paper to line the bottom of a 9-inch (2-inch deep) round cake pan. Butter and line pan. Butter lining, then flour pan, tapping out excess. Set aside.

2. Whisk together flour, baking powder, and salt in a medium bowl; set aside. Put butter and sugar in the bowl of an electric mixer fitted with the paddle attachment; cream on medium-high speed until pale, 2 to 3 minutes. On medium speed, add eggs one at a time, mixing well after each addition. Add vanilla, and mix, scraping down sides of bowl. On low speed, add the flour mixture in three batches, alternating with two batches of milk. Stir batter with a rubber spatula until evenly blended.

3. Pour batter into prepared pan, and smooth top with a small offset spatula. Tap pan on work surface several times to release air pockets.

4. Bake until a cake tester inserted into center comes out clean, 45 to 50 minutes. Let cake cool in pan on a wire rack, 20 minutes. Run a knife around edge of cake to loosen. Invert cake to remove from pan, and peel off parchment. Reinvert, and let cool completely on rack. Wrap in plastic wrap, and refrigerate until ready to decorate.