Preheat oven to 350°F. Spray pan with vegetable pan spray. Cream sugar and butter in mixer bowl until light and fluffy. Add eggs, vanilla and lemon flavor, mix until smooth. Add flour and baking powder, mix 30 seconds; add lemon zest and mix 1 minute more. Place batter in prepared pan. Bake 50-55 minutes or until toothpick inserted in middle comes out clean. Cool 10 minutes on cooling rack. Loosen sides; remove from pan and cool completely before serving.