Snickerdoodle Cupcakes

1 (18.25 ounce) box plain white cake mix
1 cup whole milk
1 stick (1/2 cup) butter melted
3 large eggs
1 teaspoon vanilla extract
2 teaspoons ground cinnamon

Frosting:
1 stick butter
3 3/4 cups confectioners' sugar
3-4 tablespoons milk
1 teaspoon vanilla extract
1 tablespoon ground cinnamon

Heat oven to 350 degrees. Place liners in a cupcake tin.

Place cake mix, milk, melted butter, eggs, vanilla extract and cinnamon in a large mixing bowl. Blend for three minutes (stop to scrape once). Pour into muffin liners and bake for 22-25 minutes. Allow to cool completely before frosting.

Frosting: Beat butter until fluffy. Add remaining ingredients and mix well.