French Onion Soup

Caramelize onions Melt the butter in a medium Dutch oven or stockpot over medium-high heat. Add onions and sprinkle with sugar. (The pot will be quite full but the onions will cook down significantly.) Cook, stirring only occasionally to prevent sticking, until onions are translucent, about 15 minutes. Reduce heat to medium and continue cooking, stirring frequently, until onions have turned deep brown, 30 to 45 minutes more. (If the onions are sticking to the bottom of the pot, or browning unevenly, stir in a tablespoon of water. Adjust heat if onions are cooking too quickly or too slowly.)

Make soup Sprinkle flour over onions and stir to combine, then stir in wine and Cognac. Bring to a simmer over medium heat. Cook 2 minutes, then stir in stock. Partially cover the pot and cook until flavors have melded, 20 to 25 minutes. Season with salt and pepper.

Meanwhile, toast croutons Heat broiler. Spread bread slices on a baking sheet and broil, turning once, until lightly toasted, 2 to 4 minutes (watch carefully so they don’t burn). Brush both sides with the melted butter.