Snickerdoodle Cake

From the Cake Mix Doctor

1 pkg. (18.25 ounces) plain white cake mix
1 cup whole milk
8 tbls. (1 stick)butter, melted
3 large eggs
1 tsp. pure vanilla extract
2 tsp. ground cinnamon

1. Place a rack in the center of the oven and preheat the oven to 350 degrees. Grease 9x13 pan.

2. Place the cake mix, milk, melted butter, eggs, vanilla, and cinnamon in a large mixing bowl. Blend with an electric mixer on low speed for 1 minute. Stop the machine and scrape down the sides of the bowl with a rubber spatula. Increase the mixer speed to medium and beat 2 minutes more, scraping the sides down again if needed. The batter should look well combined. Pour batter in pan, smoothing it out with the rubber spatula. Place the pan in the oven.

3. Bake the cakes until they are golden brown and spring back when lightly pressed with your finger, 27 to 29 minutes. Remove the pan from the oven and place them on wire racks to cool for 10 minutes. Allow it to cool completely, 30 minutes more.

4. Frost with Cinnamon Buttercream Frosting below.

Cinnamon Buttercream Frosting

8 tbls. (1 stick) butter, at room temperature.
3 3/4 cups confectioners' sugar, sifted
3 to 4 tbls. milk
1 tsp. pure vanilla extract
2 tsp. cinnamon

1. Place the butter in a large mixing bowl. Blend with an electric mixer on low speed until fluffy, 30 seconds. Stop the machine and add confectioners' sugar, 3 tablespoons milk, vanilla, and cinnamon. Blend with the mixer on low speed until the sugar is incorporated, 1 minute. Increase the speed to medium and beat until light and fluffy, 1 minute more. Blend in up to 1 tablespoon milk if the frosting seems to stiff.