My mother often made these brownies on the spur of the moment. She’d see a bunch of kids in the house, and an hour later, she’d offer all of us a treat. “Let’s have a bite of brownie!” she would announce, and proceed to hand out small, warm squares.
I have no doubt that this recipe came from the back of a box at some point, but I only have the small index card she wrote in her beautiful penmanship. It’s a simple formula: chocolate, butter, sugar, eggs, and flour, all stirred together in one pot.