French Onion Soup

• 5 pounds [2.3 kg] onions, preferably red
• 4 tablespoons butter

Peel and slice the onions as thin as you can. This is easiest with a plastic vegetable slicer, called a Benriner cutter. Melt the butter over medium heat in a wide, heavy-bottomed pot large enough to hold the sliced onions. Add the onions and stir every few minutes over medium heat until they soften and release liquid, about 15 minutes. At this point, you