Step 1: Caramelize the Onions
Heat butter and olive oil in a large pot over medium heat.
Add the sliced onions and cook slowly for 25–30 minutes, stirring occasionally.
The onions should become soft, golden brown, and caramelized.
Add the sugar during cooking to help them caramelize.
Step 2: Add Garlic
Add the minced garlic and cook for 1 minute until fragrant.
Step 3: Deglaze the Pot
Pour in the white wine and scrape the bottom of the pot to release the flavorful bits.
Let it cook for 2–3 minutes until slightly reduced.
Step 4: Add the Broth
Pour in the beef broth.
Add:
- thyme
- bay leaf
- salt
- black pepper
Bring the soup to a gentle simmer and cook for 20 minutes.
Step 5: Prepare the Bread
Preheat the oven to 375°F (190°C).
Place baguette slices on a baking sheet and toast them for 5–7 minutes until crisp.
Step 6: Assemble the Soup
Ladle the hot soup into oven-safe bowls.
Place toasted bread slices on top of the soup.
Sprinkle generously with Gruyère and Parmesan cheese.
Step 7: Broil the Cheese
Place the bowls under the oven broiler for 2–3 minutes until the cheese melts and becomes golden and bubbly.
Step 8: Serve
Carefully remove from the oven and serve immediately while hot.
✅ Tips for the Best French Onion Soup
- Slow caramelization of onions is the secret to deep flavor.
- Gruyère cheese melts beautifully and gives authentic taste.
- Use homemade beef broth if possible for richer flavor.
- A splash of balsamic vinegar can enhance the sweetness of onions.
If you want, I can also show you:
- The secret restaurant trick for darker French onion soup
- Slow cooker French onion soup
- French onion soup with red wine
- Cheesy French onion pasta recipe.
