1. Preheat oven to 400F.
2. Beat butter and sugars together until fluffy, about 3 minutes. Add eggs and vanilla, beat well. At low speed, add baking soda, powder, salt and flour, alternating with buttermilk, until just blended.
3. Spoon batter into greased and floured 9-inch cake or springform pan. Top with strawberries and sprinkle with extra turbinado sugar. Bake 30-40 minutes or until pick inserted into center comes out clean. Cool, then remove the springform ring. Sprinkle with powdered sugar. Serves 10.