Cinnamon Swirl Coffee Cake

1 package (18.5 ounces) plain butter recipe golden cake mix
1 cup sour cream

3/4 cup vegetable oil

1/4 cup granulated sugar


4 large eggs
1 Tbsp pure vanilla extract

1/2 cup packed light brown sugar (for topping)

1 Tbsp ground cinnamon (for topping)


Preheat oven to 325 degrees.  Lightly mist two 9-inch (or one 13 x 9) metal cake pans with vegetable oil spray, then dust them with flour.  Shake out excess flour.  Place the cake mix, sour cream, oil, granulated sugar, eggs and vanilla in a large mixing bowl and beat on low speed until ingredients are incorporated, 30 seconds.  Scrape down sides with rubber spatula.  Increase mixer speed to medium and beat until mixture lightens and is smooth , 2 minutes longer scraping down the side of the bowl again if needed.  Pour half the cake batter into the 2 prepared pans dividing it evenly.  Smooth the tops with the rubber spatula.  Combine the brown sugar and cinnamon in a small bowl.  Spoon half of the topping over the batter, dividing it evenly.  Pour the remaining cake batter over the topping dividing evenly.  Spoon the rest of the topping over the cake batter.  Bake the cakes until they are golden brown and tops spring back when lightly pressed with a finger - about 40 to 45 minutes.  Transfer pans to wire racks and let cakes sit until nearly cool - 20 minutes.  Slice and serve the cakes while still a bit warm.