Preheat oven to 350F (175C) with rack on the lowest position.

Sift cake flour, powdered sugar, cocoa powder, and ground cinnamon together three times in a bowl.

Set the sifted flour mixture aside.

In a large mixing bowl, beat egg whites, cream of tartar, and vanilla extract on medium speed until soft peaks form.

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

Sift about 1/4 of the flour mixture over the beaten egg whites and gently fold it in.

Repeat the process, folding in the remaining flour mixture in fourths.

Pour the batter into an ungreased 10-inch tube pan.

Bake for 40-45 minutes, or until the top springs back when lightly touched.

Immediately invert the cake (in the pan) and cool thoroughly.

Loosen the sides of the cake from the pan and remove the cake.