Rippled Coffee Cake

Ingredients
1 (18.25 ounce) package yellow cake mix
1 cup sour cream
4 eggs
2/3 cup vegetable oil
1 cup packed brown sugar tablespoon ground cinnamon

ICING:
cups confectioners’ sugar
1/4 cup milk
2 teaspoons vanilla extract

Directions
In a mixing bowl, combine dry cake mix, sour cream, eggs and oil; beat well. Spread half of the batter into a greased 13-in. x 9-in. x 2- in. baking pan. Combine brown sugar and cinnamon; sprinkle over batter. Carefully spread remaining batter on top. bake at 350 degrees F for 30-35 minutes or until a toothpick inserted near the center comes out clean. Combine icing ingredients and drizzle over warm cake.