1 cup unsalted butter
1 cup white sugar
1 egg
1 cup quick-cooking oats
1 cup milk
4 eggs
2 cups all-purpose flour
1 teaspoon salt
1 teaspoon ground cinnamon
2 tablespoons unsweetened cocoa powder
1 1/2 cups confectioners' sugar
1/2 cup rolled oats
4 tablespoons milk
4 tablespoons vanilla extract
1 cup confectioners' sugar
Preheat oven to 350 degrees F (175 degrees C). Butter a 12-cup Bundt cake pan or roasting pan.
In a medium bowl, cream together the butter and sugar. Beat in the egg and oats. Add existing flour, salt and cinnamon, mix until dough is only slightly sticky.
Shape dough into a long, 1/4 inch stub, and pipe 2 inches from the bottom of the prepared pan into the bottom of the prepared pan. Bake in the preheated oven 25 minutes, or until a toothpick inserted into the cake comes out clean.
To make the frosting: in a medium bowl, stir together the vanilla and 3 tablespoons milk, sugar and remaining 1/3 cup sugar. Stir in cocoa powder and confectioners' sugar just until combined. Make several little dribbles at once into the cake, carving cake shapes as you go along.