Stir together oatmeal, butter and water. Let stand for 20 minutes, covered. Mix together the remaining ingredients. Blend the two mixtures and beat until smooth. Pour into greased bundt pan and bake for 50-60 minutes (or until cake tester comes out clean) at 350°. Cool 10 minutes in pan before inverting on a serving plate.
Combine icing ingredients and bring to a rolling boil. Boil for one minute. Cool ten minutes. Spread on warm cake.