This cinnamon sugar cake has fluffy layers, a salted brown sugar cinnamon filling, and a whipped vanilla buttercream frosting the outside!
For the cake:
½ cup unsalted butter, at room temperature
¼ cup canola oil
½ cup sugar
¼ cup brown sugar, packed
1 large egg, at room temperature
1 large egg yolk, at room temperature
1–3/4 cups cake flour
½ teaspoon baking powder
½ teaspoon baking soda
½ teaspoon salt
3/4 cup milk, at room temperature
1 teaspoon vanilla extract
For the filling:
1/2 cup unsalted butter, at room temperature
1/2 cup brown sugar
1–1/2 cups powdered sugar
1 teaspoon vanilla
1–1/2 teaspoons cinnamon
1/2 teaspoon salt
2 tablespoons milk or cream
For the buttercream:
¾ cup unsalted butter, at room temperature
3 cups powdered sugar
1 teaspoon vanilla extract
¼ teaspoon salt
1–2 tablespoons milk or cream
To prepare the cake:
Preheat the oven to 350. Lightly grease two 6” round pans and cut out parchment paper rounds to fit into the bottom of them. Set aside.
In a large bowl or the bowl of a stand mixer, cream together the butter, canola oil, sugar, and brown sugar until smooth, about a minute and a half. Add the egg and yolk and stir until combined. Scrape the sides of the bowl and stir in any unincorporated bits. Add half of the cake flour, the baking powder, baking soda, and salt and stir on low to combine. Add ¼ cup of the milk as well as the bourbon and vanilla. Stir on low. Add the remaining cake flour and milk and stir on low just until combined. Fold in any unincorporated bits. Divide the batter evenly into the prepared pans and bake in the middle of the oven for about 30-33 minutes or until the cake has puffed, turned golden, and a toothpick inserted just barely comes out clean. Don’t overbake! Set aside to cool completely.
To prepare the filling:
In a large bowl or the bowl of a stand mixer, cream the butter and brown sugar on medium until smooth, about one minute. Add the remaining ingredients and beat until smooth and combined, about 1 minute. Set aside in a different bowl while you prepare your buttercream.
To prepare your buttercream:
In the same bowl as you made your filling, cream the butter on medium speed until smooth and slightly pale, about 3 minutes. Add the powdered sugar, vanilla and salt and whip and additional minute. Add the cream and beat until smooth and fluffy, about an additional minute. Assemble your cake by spreading a small amount of buttercream on a 6” cake board. Level your cake layers using a serrated knife and place the first layer on the board. Use an offset spatula to spread the filling on the top of that first layer and place the second on top. Use an offset spatula to spread the buttercream on the outside and decorate with any remaining frosting. I like to mix the remaining filling and buttercream together to pipe décor on top! Enjoy!
For a larger cake, simply double all the ingredients and bake the batter in 2 9″ pans! Bake time may be longer.