HEAT oven to 350°F. COAT bottom and sides of 9- to 12-cup fluted tube pan with cooking spray.

MIX flour, cocoa, baking powder, baking soda, salt and cinnamon in medium bowl.

BEAT sugar and butter in mixer bowl on medium speed until light and fluffy. BEAT in eggs, applesauce and vanilla. Reduce speed to low. ADD dry ingredients; beat until blended. Gently STIR IN zucchini.

POUR batter into prepared pan. BAKE in 350°F oven until wooden pick inserted in center comes out clean, 60 to 70 minutes. COOL on wire rack 10 minutes. LOOSEN cake from sides of pans with thin knife. Gently SHAKE cake from pan onto serving plate. SPRINKLE with powdered sugar.