Introduction
French onion soup, or 'soupe à l'oignon,' has been a staple of French cuisine since the 18th century, originating in Paris's Les Halles market where workers would enjoy this hearty soup in the early morning hours. This keto adaptation honors the traditional preparation method of slowly caramelizing onions until they develop their characteristic sweetness, while innovating on the classic recipe by eliminating the bread and focusing on the rich, cheese-crowned top. The result is a dish that proves how classic recipes can be thoughtfully adapted for modern dietary needs without sacrificing their soul.
Ingredients
• 6 large yellow onions (about 3 pounds), thinly sliced
• 4 tablespoons unsalted butter
• 2 tablespoons olive oil
• 8 cups beef broth (preferably homemade or low-sodium)
• 2 cups chicken broth
• 1/2 cup dry white wine (optional)
• 2 sprigs fresh thyme
• 2 bay leaves
• 2 cloves garlic, minced
• 1 teaspoon Worcestershire sauce
• 8 ounces Gruyère cheese, grated
• 2 ounces Parmesan cheese, grated
• 1 teaspoon black pepper, freshly ground
• 1 teaspoon sea salt, or to taste
Step 1:
In a large Dutch oven, melt butter with olive oil over medium heat
Step 2:
Add sliced onions and cook for 45-60 minutes, stirring every 5-10 minutes, until deeply caramelized and golden brown
Step 3:
Add minced garlic and cook for 1 minute until fragrant
Step 4:
Pour in white wine (if using) and scrape bottom of pot to deglaze. Simmer until wine is nearly evaporated, about 3-4 minutes
Step 5:
Add beef broth, chicken broth, thyme sprigs, bay leaves, and Worcestershire sauce. Bring to simmer and cook for 20-25 minutes
Step 6:
Season with salt and pepper to taste
Step 7:
Preheat broiler. Ladle soup into oven-safe bowls and top with mixed Gruyère and Parmesan cheese
Step 8:
Place bowls under broiler for 2-3 minutes until cheese is melted, bubbly, and lightly browned
Q: Can I make this ahead of time?
A: Yes, prepare soup base up to 3 days ahead and add cheese topping just before serving
Q: Why are my onions not caramelizing?
A: Ensure pan isn't overcrowded and maintain medium heat. Patience is key - proper caramelization takes 45-60 minutes
Q: Is this recipe truly keto-friendly?
A: Yes, by omitting traditional bread and using only low-carb ingredients, this version is keto-compatible
• For cheese, Emmental can be substituted for Gruyère if needed.
• Use yellow onions for best caramelization results.
• Low-sodium broths are recommended to better control salt content.
• Wine is optional but adds depth - can be replaced with additional beef broth.
• Contains dairy - not suitable for lactose-intolerant individuals.
• Gluten-free if using certified gluten-free Worcestershire sauce.
Serve immediately while cheese is hot and bubbly. Careful, bowls will be very hot
Store soup without cheese topping in airtight container in refrigerator for up to 4 days. Reheat and add cheese before serving
The key to perfect French onion soup is properly caramelizing the onions - don't rush this step
- Slice onions uniformly for even caramelization
- Don't stir onions too frequently while caramelizing to achieve proper browning
- Use oven-safe bowls that can withstand broiler temperatures
For dairy-free version, omit cheese and top with caramelized mushrooms. For vegetarian version, use vegetable broth instead of beef and chicken broth
Pair with a dry red wine like Burgundy or a crisp white wine like Chablis
Best served during fall and winter months
Contains dairy (butter, Gruyère cheese, Parmesan cheese). Check Worcestershire sauce for gluten if celiac. No nuts, eggs, or shellfish
