- 1 (18.25 ounce) package chocolate cake mix
- 1 cup milk
- 3 eggs
- 1/2 cup butter, melted
- 1 teaspoon ground cinnamon
- 1 teaspoon vanilla extract
- 1 teaspoon cinnamon sugar, or as needed
- 1/2 cup butter
- 1/2 cup butter-flavored shortening
- 1 pinch sea salt
- 1 teaspoon vanilla extract
- 1 tablespoon ground cinnamon
- 1 tablespoon unsweetened cocoa powder
- 3 cups confectioners' sugar
- 1/4 cup milk
- 2 cups confectioners' sugar, or more as needed
- Preheat an oven to 350 degrees F (175 degrees C).
- Line 24 muffin cups with paper liners.
- Beat together the chocolate cake mix, 1 cup milk, eggs, 1/2 cup melted butter, 1 teaspoon cinnamon, and 1 teaspoon vanilla extract in a bowl with an electric mixer on low speed until moist. Beat for 2 more minutes on medium speed.
- Fill each muffin cup about 2/3 full of batter.
- Sprinkle the cupcakes with cinnamon sugar.
- Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 15 minutes.
- Cool in the pans for 10 minutes before removing to cool completely on a wire rack.
- Cream together 1/2 cup butter and shortening in a bowl until smooth.
- Stir in sea salt, 1 teaspoon vanilla extract, 1 tablespoon cinnamon, cocoa powder, and 3 cups confectioners' sugar.
- Stir in milk.
- Mix in 2 more cups confectioners' sugar or as needed until desired consistency is achieved.
- Spread the frosting on the cooled cupcakes.