Chop four squares of white chocolate and melt the other four; set both aside. In a bowl, cream butter and 2 cups sugar until light and fluffy, about 5 minutes. Add eggs, one at a time, beating well after each addition. Stir in extracts and the melted chocolate.
Combine flour, baking powder, salt and baking soda; add to the creamed mixture alternately with sour cream. Beat just until combined.
Grease a 10-in. fluted tube pan. Sprinkle with the remaining sugar. Pour a third of the batter into pan. Sprinkle with half of the chopped chocolate. Repeat. Pour remaining batter on top.
Bake at 350° for 55-60 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes; remove from pan to a wire rack to cool completely. Drizzle semisweet and white chocolate over cake. Garnish with strawberries if desired.