"My brownies keep burning on the outside before they are cooked on the inside. I followed the recipe, and even used an oven thermometer to see if that was the problem. What could I be doing wrong?"
My guess is you are making your browniesin a glass pan. Glass baking dishes conduct heat really well, which is great for making casseroles but not so great when your recipe has a lot of sugar, which will burn before your sweet treat is cooked all the way through. Try baking them in a metal pan next time and see if they turn out better.
Recipe: So-Good Brownies