Preheat oven to 350°. Grease and lightly flour a 9-inch springform pan; set aside.
Beat cake mix, Hellmann's® or Best Foods® Real Mayonnaise, water, eggs and cinnamon 30 seconds in large bowl with electric mixer on low speed. Beat on medium speed, scraping sides occasionally, 2 minutes. Pour batter into prepared pan.
Bake 40 minutes or until toothpick inserted in center comes out clean. Cool on wire rack 10 minutes. Remove from pan and cool completely. Frost and decorate as desired.