Chocolate Cinnamon Angel Food Cake

Bring egg whites to room temperature, about 1 hour.

Meanwhile, sift flour, cocoa, powdered sugar, and cinnamon together three times. Set aside.

In a large mixer bowl, beat the egg whites, cream of tartar, and vanilla with an electric mixer on medium speed until soft peaks form.

Gradually add the sugar, 2 tablespoons at a time, beating on high speed until stiff peaks form.

Transfer to a larger bowl if needed. Sift about one-fourth of the flour mixture over the beaten egg whites. Fold in gently. Repeat, folding in the remaining flour mixture in fourths.

Pour into an ungreased 10 inch tube pan. Bake on the lowest rack in the oven at 350 degrees F for 40-45 minutes or until the top springs back when touched.

Immediately invert cake (leave in pan). Cool thoroughly. Loosen sides of cake from pan and remove.