Pour boiling water over quick oats and let sit 20 minutes. Do not drain.
Combine butter and sugars and mix on medium in the mixer until light and fluffy. Add eggs one at a time and beat well. Add dry ingredients and mix until well blended. Add oatmeal and finish mixing well.
Bake at 350 degrees for 35 to 40 minutes until cake is done. While cake is baking, make the topping. Mix all ingredients until mixed well. Spread on hot cake, put cake back in oven under the broiler until the top is brown and bubbly. Remove and let cool. Serve warm or cold.