Onion soup (soupe a l'oignon)

Posted by isabel on Nov 15th 2022

Onion soup (soupe a l'oignon)

Serves: 2 - Prep time: 20 min - Cook time: 40 min


  • Medium saucepan
  • Spoon
  • Oven-safe bowls or crocks
  • Ladle


  • 4 tsp (20 g) unsalted butter
  • 1/2 onion (about 200 g), peeled and diced
  • 1 tbsp + 1 tsp all-purpose flour (10g)
  • 2 cups vegetable broth OR 1/2 bouillon cube plus 2 cups (1/2 L) hot water
  • 2 slices country bread or 6 thin slices baguette
  • 1/2 c (50g) shredded Swiss cheese
  • Salt and pepper to taste


  1. Preheat the oven to 350 °F.
  2. In a medium saucepan set over medium heat, melt the butter.Add the diced onion and cook, stirring with a spatula, until golden.When the onion is cooked, add the flour and stir until the onions, butter, and flour are well combined.
  3. Wet the mixture with a little bit of broth and stir vigorously. Then, pour in the rest of the broth and let simmer for about 30 minutes, until the broth thickens slightly. Season to taste with salt and pepper (if necessary) and ladle the soup into oven-safe bowls or crocks.
  4. Top each bowl of soup with a slice of country bread (or 2 to 3 slices baguette) and sprinkle the bread with cheese.
  5. Bake in the oven for about 10 minutes to melt the cheese.