Preheat oven to 325°F. Mix flour, baking powder and baking soda in medium bowl. Beat 1 cup of the granulated sugar and 1/2 cup (1 stick) butter in large bowl with electric mixer on medium speed until lightly and fluffy. Beat in eggs, 1 at a time, until just combined. Stir in 2 teaspoons of the vanilla. Gradually add flour mixture alternately with buttermilk, beating on low speed after each addition until smooth. Pour into greased 9-inch round cake pan.
Bake 30 to 35 minutes or until toothpick inserted in center comes out clean.
Meanwhile, melt remaining 1/2 cup (1 stick) butter in small saucepan on medium heat until caramel color. Mix remaining 3/4 cup granulated sugar, water and 3 teaspoons of the remaining vanilla in small bowl. Add to browned butter, stirring with wire whisk until well blended and smooth. Remove from heat. Cool slightly.
Poke holes in warm cake with skewer at 1-inch intervals. Slowly pour warm butter sauce over cake. Cool in pan 1 hour. Mix pineapple, raspberries, confectioners’ sugar and remaining 1 teaspoon vanilla. Invert cake onto serving platter. Slice cake and serve warm, topped with fruit mixture.