French Onion-Style Soup with Cheese Toast

What you’ll need

Let’s do this

1. 1

   Start the onions

   Melt the butter with the oil in a large heavy saucepan or Dutch oven over medium heat. Add the onions and salt and stir to coat. Cook for 10 minutes, stirring often, until the onions begin to soften.

2. 2

   Brown patiently

   Reduce the heat to medium-low and cook for another 40–50 minutes, stirring every few minutes, until the onions are deeply golden and jammy. If dark patches form on the pot before the onions are ready, add 1 tablespoon water and scrape them up. Lower the heat if the onions begin to burn.

3. 3

   Build the broth

   Stir in the garlic for 30 seconds. Add 1/2 cup of the measured broth and scrape up the browned bits. Add the remaining 5 1/2 cups broth, thyme, bay leaf, and pepper. Bring to a simmer and cook uncovered for 20 minutes.

4. 4

   Prepare the bread

   During the final 10 minutes of simmering, heat the oven to 425°F/220°C. Put the bread on a metal baking sheet and toast for 5–7 minutes until dry and lightly golden.

5. 5

   Melt the cheese

   Switch the oven to its broil setting. Divide the Gruyère among the toast slices and place the sheet about 6 inches below the heating element. Broil for 1–3 minutes, watching continuously, until the cheese bubbles and develops golden spots.

6. 6

   Finish and serve

   Remove the bay leaf and stir the balsamic vinegar into the soup. Divide the hot soup among four bowls and place a cheese toast on each. Serve carefully while hot.