Preheat oven to 350 °F. Grease a 13 x 9 inch casserole dish.
Cream together butter and two sugars. Blend in oats, water, applesauce, and eggs until smooth.
Add in all dry ingredients; flour, salt, baking powder, baking soda, and cinnamon. Blend again until smooth.
Pour batter into greased casserole dish and bake for 30-35 minutes or until toothpick comes out clean. Take out of oven and set oven to broil.
Icing
In a saucepan, bring butter, brown sugar, and milk to a boil.
Take off of heat and stir in shredded coconut. Pour on top of hot cake. Set cake under broiler until the entire top starts boiling. Take out of oven and let completely cool.