Fresh Upside Pineapple Cake
- Put oven rack in middle position and preheat oven to 350°F.
- Sift together flour, baking powder and soda, and salt into a bowl. Cut pineapple crosswise into 1/4-inch-thick wedges.
- Butter a 9-inch round cake pan (2 inches deep) lightly on side and generously on bottom of pan using 1/2 stick butter. Sprinkle all of brown sugar evenly over bottom and arrange pineapple over it, starting in center of pan and overlapping slices slightly.
- Beat together remaining stick butter, granulated sugar, and vanilla with an electric mixer at medium speed until light and fluffy, about 2 minutes, then add eggs 1 at a time, beating well after each addition. Reduce speed to low and add flour mixture alternately with buttermilk in batches, beginning and ending with flour and mixing just until batter is smooth.
- Spread batter evenly over pineapple and bake until a wooden pick inserted in center of cake comes out clean, 40 to 45 minutes. Cool 15 minutes in pan on a rack, then invert cake onto a plate and remove pan. Cool to room temperature.