Preheat the oven to 350ºF. Line mini cupcake pans with 72 mini cupcake liner or line a regular-size cupcake or muffin pan with 24 cupcake liners.
Sift together the cake flour, baking powder, and salt into a bowl, and set aside.
Combine the graham crackers crumbs and brown sugar in a small bowl and pour in the melted butter. Stir until combined, and set aside.
In the bowl of an electric mixer fitted with a paddle attachment, beat the butter on medium speed until creamy. Gradually add the sugar and beat about 3 minutes more, or until light and fluffy. Scrape down the sides of the bowl. Reduce the speed to low and add the egg yolks one at a time, beating well after each addition. Scrape down the sides of the bowl. Beat in the vanilla extract and cinnamon. On low speed, mix in 1/3 flour mixture and 1/2 the milk, repeating alternating between the flour and milk, beginning and ending with the flour mixture. Mix just until the flour is incorporated. Do not overbeat once the flour mixture is added. Scrape down the sides of the bowl.
With an electric hand mixer, beat the egg whites until medium-stiff peaks form and fold into the batter. Fold in the graham cracker-brown sugar mixture. Scoop the batter into the lined mini cupcake pan or regular-size cupcake pan. Bake 22 minutes for mini cupcakes or 27 minutes for regular-size cupcakes, or until a cake tester comes out clean. Cool the cupcakes completely before frosting.
CINNAMON SUGAR GRAHAM CREAM CHEESE ICING:.
Combine the graham cracker crumbs and brown sugar in a small bowl and pour in the melted butter. Stir until combined and set aside.
In the bowl of an electric mixer, fitted with the paddle attachment, beat together the cream cheese and butter on medium speed until smooth. Beat in the vanilla extract, cinnamon, and salt. Reduce the speed to low, and add the confectioners' sugar until well blended. Increase the speed to high and beat about 3 minutes more, or until light and creamy. Fold in the graham cracker-brown sugar mixture. Place the icing in a pastry bag fitted with a pastry tip. Pipe the icing on the cooled cupcakes. Garnish the cupcakes with graham cracker crumbs, a piece of cinnamon sugar graham cracker, and a sprinkling of cinnamon.
Yield: approximately 3 1/2 cups.