5. Spoon 2 tablespoons of cupcake batter into each cupcake liner. Top with 1 teaspoon of the cinnamon-sugar mixture. Top with 1 heaping tablespoon of cupcake batter, until the cupcake liners are about 3 / 4 full. Some of the cinnamon-sugar filling from the center layer may peek through the top layer of batter. Top each cupcake with 1 more teaspoon of the cinnamon-sugar.
6. Bake the cupcakes for 19-21 minutes or until a toothpick inserted in the center comes out clean. Allow to cool completely before frosting.
7. For the frosting, stir 1 tablespoon of cinnamon into the frosting. Pipe onto cupcakes.
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