Cinnamon-Chocolate Ribbon Cake

PreparationFor cake: Position rack in center of oven and preheat to 325°F. Butter 9 1/2- to 10-inch-diameter angel food cake pan. Line pan bottom with waxed paper; butter paper. Stir chocolate in top of double boiler set over simmering water until melted. Remove from over water. Sift flour, baking powder and salt into medium bowl. Using electric mixer, beat eggs in large bowl until foamy. Add sugar and beat until thick and fluffy, about 3 minutes. Gradually beat in oil. Beat in milk and vanilla. Add dry ingredients and beat just until blended. Transfer 1 1/2 cups batter to small bowl; mix in melted chocolate. Mix cinnamon into remaining batter. Spread half of cinnamon batter in prepared pan. Spoon chocolate batter over. Top with remaining cinnamon batter. Using small knife, swirl batters to marbleize slightly. Bake cake until test inserted near center comes out clean, about 1 hour 10 minutes. Cool cake in pan on rack 10 minutes. Cut around pan sides and center tube. Turn cake out onto rack; peel off paper. Turn right side up; cool. Glaze: Combine cream, butter and corn syrup in heavy medium saucepan. Stir over medium heat until mixture simmers. Remove from heat; add chocolate. Whisk until chocolate melts and glaze is smooth. Let cool until glaze thickens slightly but is still spreadable, stirring occasionally, about 30 minutes. Place cake on platter. Slide waxed paper strips under edge of cake. Spread glaze over cake. Remove paper. Chill until glaze sets. (Can be made 2 days ahead. Cover and keep chilled. Let stand at room temperature 1 hour before serving.)

PreparationFor cake: Position rack in center of oven and preheat to 325°F. Butter 9 1/2- to 10-inch-diameter angel food cake pan. Line pan bottom with waxed paper; butter paper. Stir chocolate in top of double boiler set over simmering water until melted. Remove from over water. Sift flour, baking powder and salt into medium bowl. Using electric mixer, beat eggs in large bowl until foamy. Add sugar and beat until thick and fluffy, about 3 minutes. Gradually beat in oil. Beat in milk and vanilla. Add dry ingredients and beat just until blended. Transfer 1 1/2 cups batter to small bowl; mix in melted chocolate. Mix cinnamon into remaining batter. Spread half of cinnamon batter in prepared pan. Spoon chocolate batter over. Top with remaining cinnamon batter. Using small knife, swirl batters to marbleize slightly. Bake cake until test inserted near center comes out clean, about 1 hour 10 minutes. Cool cake in pan on rack 10 minutes. Cut around pan sides and center tube. Turn cake out onto rack; peel off paper. Turn right side up; cool. Glaze: Combine cream, butter and corn syrup in heavy medium saucepan. Stir over medium heat until mixture simmers. Remove from heat; add chocolate. Whisk until chocolate melts and glaze is smooth. Let cool until glaze thickens slightly but is still spreadable, stirring occasionally, about 30 minutes. Place cake on platter. Slide waxed paper strips under edge of cake. Spread glaze over cake. Remove paper. Chill until glaze sets. (Can be made 2 days ahead. Cover and keep chilled. Let stand at room temperature 1 hour before serving.)