Cooking Instructions:

Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking pan with cooking spray or butter to prevent sticking.

In a large mixing bowl, combine the yellow cake mix, sour cream, vegetable oil, and eggs. Beat the mixture with an electric mixer on medium speed for about 2 minutes until well combined and smooth.

In a separate bowl, mix together the granulated sugar, brown sugar, and ground cinnamon. This mixture will create the delicious swirl in the cake.

Pour half of the cake batter into the prepared baking pan and spread it evenly. Sprinkle half of the cinnamon-sugar mixture over the batter.

Add the remaining cake batter on top of the cinnamon-sugar layer, then sprinkle the rest of the cinnamon-sugar mixture over the top.

Using a knife or a skewer, gently swirl the batter and cinnamon-sugar mixture together to create a marbled effect. Be careful not to overmix.

Bake in the preheated oven for 35 to 40 minutes, or until a toothpick inserted into the center of the cake comes out clean.

While the cake is baking, prepare the glaze by mixing the powdered sugar and milk in a small bowl until smooth. Adjust the consistency by adding more milk if necessary.

Once the cake is done baking, allow it to cool in the pan for about 10 minutes. Then drizzle the glaze over the warm cake before serving.