Brown Sugar Cinnamon Cake

1 (18.25 ounce) box yellow cake mix with pudding
1/2 cup vegetable oil
4 eggs
1 (16 ounce) container sour cream
1 cup brown sugar
4 teaspoons cinnamon
1 cup confectioners' sugar
1 teaspoon vanilla extract
1 to 3 teaspoons hot water

Mix cake mix, oil, eggs and sour cream and pour into a greased 9 x 13-inch glass baking pan. Pour one-half mixture into cake pan.

Mix brown sugar and cinnamon and spread evenly across batter. Pour other half batter on top and bake at 350 degrees F for 45 minutes to one hour. (Check after 45 minutes - middle should begin to pass the wooden pick test.)

Mix confectioners' sugar, vanilla extract and 1 tablespoon warm water, adding more water if necessary to make glaze thin enough to spread on warm cake.

Serve warm!