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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