- 4 tbsp unsalted butter
- 2 tbsp olive oil
- 4 cups yellow onion, thinly sliced
- 2 tbsp salt
- 1 tsp sugar
- 2 tbsp flour
- 4 cups beef broth (or water)
- Grated Gruyere cheese
- ½ loaf of baguette
- In a large pot, melt the butter over medium heat and add olive oil. Stir it around and once the butter starts to froth, add onions and salt. Lower the heat and slowly cook onions for about 15 minutes until they become softened and browned. Stir occasionally to prevent any sticking or burning.
- Once the onions are properly cooked, add flour and sugar. Whisk everything until well combined, then add the broth. This mixture should nicely thicken at this point.
- Bring the heat back up and let everything come to a boil. Then, immediately lower the heat and leave the mixture to simmer for about 15 to 20 minutes.
- In the last 5 minutes of cooking, prepare the bread by cutting your loaf into 1-inch slices. Place them on a baking sheet lined with parchment paper. Sprinkle some grated cheese on top of each slice and broil them for about 3 minutes until the cheese has melted.
- Pour the soup in a bowl and place a slice of bread on top, gently pushing it down slightly so it submerges into the soup. Serve while hot and enjoy!