Snickerdoodle Cupcakes

I have an obsession with cupcakes. I am not ready to reveal my secret recipe yet =) but here is one that is easy and really good. It only requires one bowl unlike the other ones I have tried recently. I prefer chocolate but for those that don't (my husband) these are good!

Snickerdoodle Cupcakes (these can be made into a cake too- whichever you prefer)

1 package plain white cake mix
1 cup whole milk
1 stick of butter melted
3 large eggs
1 teaspoon vanilla extract
2 teaspoons ground cinnamon

Frosting:
1 stick butter
3 3/4 cup confectioners sugar
3-4 Tablespoons milk
1 teaspoon vanilla extract
1 Tablespoon ground cinnamon

Preheat oven to 350 degrees and flour & grease 2 9" pans (for cakes) or line your cupcake tin. Place cake mix, milk, melted butter, eggs, vanilla, and cinnamon in a large mixing bowl. Blend for three minutes (stop to scrape once). Pour into pans and bake for 27-29 minutes (for cake) or 22-25 minutes (for cupcakes). Allow the cakes to cool completely.

Beat butter until fluffy for frosting. Add all other ingredients.