Light and fluffy sour cream cake with a thick cinnamon swirl and cream cheese frosting. All of the flavors of a cinnamon roll in a delicious homemade cake!
Preheat oven to 350°F with a rack in the center. Grease a 13x9x2-inch baking pan.
In a large bowl whisk flour, baking powder, baking soda and salt.
Using a hand mixer or stand mixer fitted with the paddle attachment, beat sugar and butter until smooth and creamy. Beat in eggs 1 at a time, then vanilla extract, scraping the sides and bottom of the bowl as needed. Add the flour in three additions and the sour cream in two additions, beginning and ending with the flour. Once combined, add milk and beat until incorporated, scraping the sides and bottom of the bowl as necessary. Spread batter in prepared pan (it will be thick).
Cinnamon filling:
Mix together all ingredients until well combined (I use a fork or a rubber spatula). Drop small spoonfuls of filling all around on the top of the cake batter.
Use a thin knife to swirl the filling around and down into the batter.
Bake the cake for 30-40 minutes, until a toothpick inserted into the center comes out clean. When checking for doneness make sure you're checking the cake portion, don't worry about the cinnamon swirls. Peek at the cake around 25 minutes. If it begins to get dark, place a piece of foil loosely over the top. Place the pan on a wire rack to cool completely.
Frosting:
Using a hand mixer or stand mixer, beat cream cheese and butter until combined. Beat in powdered sugar and vanilla. Increase speed to high and beat for 1-2 minutes, until light and fluffy. If desired, you can make the frosting thicker by adding more powdered sugar, or thinner by adding a splash of milk. I like it thicker than a glaze but slightly thinner than a traditional frosting (like what you would see on a cinnamon roll). Spread the frosting evenly over the top of the cooled cake.