Frosted Texas Brownies

"These Frosted Texas Brownies are made with a whisk and a bowl — no mixer required! They make a huge sheet pan and are perfect for potlucks! This Texas Brownies recipe is one my mom used to make when we were at home. I’m not sure where the recipe originated, and I see the same recipe on a lot of big sites like AllRecipes, Food.com, etc., and I’m sure it didn’t originate there either. It’s just one of those recipes that everybody has. And if you don’t, you should."