Name: Classic French Onion Soup with Gruyère Cheese
Total time: 1 hour 15 minutes total (15 prep, 60 cook)
Yield: Serves 6
Ingredients: 4 large yellow onions, thinly sliced (about 6 cups); 3 tbsp unsalted butter; 2 tbsp olive oil; 1 tsp salt; ½ tsp black pepper; 3 cloves garlic, minced; 2 tbsp all-purpose flour; ½ cup dry white wine (or sherry); 8 cups beef broth (low-sodium preferred); 2 bay leaves; 4 sprigs fresh thyme (or 1 tsp dried thyme); 1 tbsp Worcestershire sauce; ½ tsp balsamic vinegar (optional, adds depth); 1 baguette, sliced ½-inch thick; 2 tbsp olive oil or melted butter; 2 cups shredded Gruyère cheese; ½ cup shredded mozzarella (optional, for extra melt); ½ tsp garlic powder (optional); Fresh thyme leaves, for garnish

Bobbie's kitchen notes: take your time caramelising the onions — it's the key to deep, rich flavour; use a mix of Gruyère and a little mozzarella for the perfect melt and stretch; a splash of balsamic vinegar adds incredible depth; use oven-safe bowls for the best presentation; fresh thyme gives a beautiful, aromatic finish; serve immediately while the cheese is hot and bubbly; for extra richness, use homemade beef broth. Serve with a simple green salad, roasted vegetables or a charcuterie board. Nutrition per serving from Bobbie's card (approximate): 420 calories, 19 g protein, 28 g fat, 26 g carbohydrates, 2 g fibre. Vegetarian option: use vegetable broth instead of beef broth.

Ingredients

For the soup

4 large yellow onions, thinly sliced (about 6 cups)
3 tbsp unsalted butter
2 tbsp olive oil
1 tsp salt
½ tsp black pepper
3 cloves garlic, minced
2 tbsp all-purpose flour
½ cup dry white wine (or sherry)
8 cups beef broth (low-sodium preferred)
2 bay leaves
4 sprigs fresh thyme (or 1 tsp dried thyme)
1 tbsp Worcestershire sauce
½ tsp balsamic vinegar (optional, adds depth)

For the cheese toast

1 baguette, sliced ½-inch thick
2 tbsp olive oil or melted butter
2 cups shredded Gruyère cheese
½ cup shredded mozzarella (optional, for extra melt)
½ tsp garlic powder (optional)
Fresh thyme leaves, for garnish

Method

1
Caramelise the onions: in a large heavy pot, melt butter with olive oil over medium heat. Add onions and salt. Cook, stirring often, for 35–40 minutes until deeply golden and caramelised.
2
Add garlic and flour: add garlic and cook for 1 minute. Sprinkle in flour and cook for 2–3 minutes, stirring constantly, until the flour is fully absorbed and the onions are coated.
3
Deglaze and simmer: pour in white wine and scrape up any browned bits. Let simmer for 3–4 minutes. Add beef broth, bay leaves, thyme, Worcestershire sauce and balsamic vinegar. Bring to a boil, then reduce heat and simmer for 20–25 minutes.
4
Prepare the bread: preheat oven to 400°F. Brush baguette slices with olive oil or butter. Toast for 8–10 minutes until golden.
5
Assemble: ladle hot soup into oven-safe bowls. Place toasted bread slices on top and generously cover with Gruyère (and mozzarella if using).
6
Broil until bubbly: place bowls on a baking sheet and broil for 3–5 minutes, until the cheese is melted, bubbly and golden brown. Garnish with fresh thyme and serve immediately.

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From Bobbie's “Bobbie's Recipe Cards (batch 4)”. Written up by Bobbie's Kitchen · Updated 26 October 2026