1.25kg/ 2.5 lb brown / yellow onions (, peeled, halved, thinly sliced top to bottom)
3/4cup(185ml) dry white wine
2tbspflour (, plain / all purpose)
1.5litres/ 6 cups / 1.5 quarts good quality beef broth./stock OR chicken (, low sodium/salt reduced)
2dried bay leaves (or 3 fresh)
3sprigs fresh thyme
Salt and pepper
6-8slices French baguette (or other softish bread)
100g/ 3.5 oz gruyere (or mozzarella cheese, or other melting cheese of choice)
Instructions
Melt butter in a heavy based casserole pot over medium heat. Add sliced onions and stir to coat in butter.
Cook for 30 minutes on medium-low, stirring every few minutes, until the onions have softened and are semi-transparent.
Turn heat up to medium or medium-high. Add salt, and cook for a further 20-30 minutes, stirring more regularly, until onions are deep golden and sweet.
Add white wine (if using) and simmer rapidly for 2 minutes until mostly evaporated, scraping the bottom of the pot.
Sprinkle flour over the onions and cook for 1 minute, stirring constantly.
Pour in the beef broth, and add thyme and bay leaves. Bring to a simmer.
Ladle soup into oven-safe bowls. Top each with baguette slices and a generous amount of Gruyere cheese.
Broil until cheese is melted, bubbly, and golden brown. Serve immediately.
Notes
Nutrition information is an estimate, calculated automatically. Values vary with brands, substitutions and portion sizes.