Heat oven to 350°F. Spray with nonstick cooking spray and lightly flour 9-inch round cake pan. In large bowl, combine all cake ingredients except powdered sugar; mix at low speed until combined. Beat 2 minutes at medium speed. Pour batter into sprayed and floured pan.
Bake at 350°F. for 23 to 28 minutes or until top springs back when touched lightly in center. Cool in pan 30 minutes. Invert cake onto plate; remove pan. Sprinkle cake with powdered sugar.
Meanwhile, in food processor bowl with metal blade or blender container, process raspberries until smooth. Strain to remove seeds.
In small saucepan, combine raspberry puree, sugar and cornstarch; mix well. Cook over low heat, stirring constantly, until slightly thickened. Remove from heat; stir in almond extract. Serve warm sauce over cake wedges. If desired, garnish with whipped topping, slivered almonds and fresh raspberries.