Add the sugar, the remaining butter, and the rest of the olive oil. Cook for another 10 minutes over medium-high heat.

Add the flour and crushed garlic. Stir, then deglaze with the white wine. Add a bouquet garni (herb bundle) and the beef broth. Cover and simmer for 30 minutes.

Pour the soup into oven-safe bowls, place a slice of bread on top, and sprinkle with cheese. Broil at 450°F (230°C) for 5–10 minutes until golden and bubbly.