Preheat oven to 350°F. Lightly spray 9 x 5-inch loaf pan with no-stick cooking spray; set aside.
In medium bowl combine flour, baking powder and cinnamon; set aside.
In a large bowl, use an electric mixer to cream butter and sugar. Add eggs and vanilla extract; mix until blended. Add bananas. Gradually add flour mixture to butter mixture; mix well. Stir in chopped walnuts until combined.
Spread mixture into prepared pan. Bake 55 to 60 minutes or until toothpick inserted in center is clean when removed. Remove to cooling rack; cool 10 minutes. Gently loosen edges of bread from pan; remove and cool completely. Cut into slices to serve.