Frosted Buttermilk Brownies

I found this recipe many years ago in one of the cookbooks you pick up at the grocery store registers while you wait your turn in line. Luckily I copied it for many friends, so even though I cannot put my hands on the original book any more, I still have the recipe. These are delicious cake-like brownies with wonderful fudgy frosting. They are a standard to bake and take on camping trips, and pot lucks when I need to bring a dessert. The original recipe called for coconut in the frosting, but I never added it.