8-Hour Slow-Roasted French Onion Soup

02

Make the soup

1. Preheat the oven. Heat the oven to 225 degrees.

2. Start the onions on the stove, then slow-roast. Place the sliced onions, butter, olive oil, salt, sugar, and pepper in a large oven-safe pot. Toss gently to combine. Cook over medium-high heat, stirring occasionally, for about 15 minutes, until the onions begin to caramelize. Transfer the pot to the oven and roast for 7 hours, until the onions are deeply browned, soft, and sweet. Stir occasionally if you’re nearby; otherwise, let the onions do their thing while you go about your day at home. Perhaps sit outside with a book, some Taylor Swift, and enjoy a glass of wine—or two.

3. Warm the broth. Toward the end of roasting, warm all four boxes of beef broth or stock in a separate pot so it’s ready to add to the hot onions.

4. Add the remaining soup ingredients. Return the onion pot to the stovetop. Stir in the garlic and cook until softened. Add the flour and cook, stirring, until well incorporated into the onions, garlic, and butter. Stir in the warmed broth or stock, balsamic vinegar, Worcestershire sauce, bay leaves, thyme sprigs, and brandy or white wine, if using.

5. Simmer slowly. Cover and simmer over low heat for 30 minutes, until the flavors are rich and fully developed. Remove the thyme stems and bay leaves before serving.

6. Toast the bread. While the soup simmers, heat the oven to 400 degrees. Arrange the 1-inch-thick baguette slices in a single layer on a baking sheet. Brush with a little olive oil and season lightly with salt and pepper. Bake for 6–8 minutes, until toasted and golden around the edges. Remove and set aside.

7. Assemble the bowls. Turn the oven broiler to high. Ladle the hot soup into broiler-safe crocks placed on a baking sheet. Top each bowl with one large or two smaller toasted baguette slices and a generous layer of shredded or sliced Gruyère.

8. Broil and serve. Broil for 2–3 minutes, watching closely, until the cheese is melted, bubbling, and golden, with deeply browned, crisp edges. Garnish with fresh thyme leaves and serve immediately.

9. Freeze any leftovers. Freeze leftover soup in freezer-safe containers, either in one large container or in individual portions for easy reheating. Defrost in the microwave, then transfer to an oven-safe crock and reheat in the oven.