Honey Bun Cake   1 Box Yellow Cake Mix 4 eggs 3/4 cup oil 1 cup sour cream 1 teaspoon vanilla Brown Sugar Mixture 2/3 tablespoon cinnamon 1 cup brown sugar 1 teaspoon vanilla Icing 2 cups confectioners sugar 1 teaspoon milk   Mix cake mix, eggs, oil and sour cream in a large mixing bowl. In a greased ad floured pan pour half the mix and 1/2 of the brown sugar mixture, then pour second half of the batter and rest of the brown sugar on top of batter.  Run a knife blade back and forth to mix in brown sugar and cinnamon mixture into the batter to resemble a honey bun.  Bake at 325 degrees for 45 minutes. Mix confectioner's sugar and milk until a good drizzle is obtained.  Pour over warm cake and serve.