Traditional French Onion Soup

5 from 2 votes

Traditional French Onion Soup

Rich, comforting French Onion Soup made with deeply caramelized onions, a bit of smoked bacon, and a good homemade beef stock, topped with toasted bread and melted Gruyère.

Prep Time15

Cook Time1 15

Total Time1 30

Course: Appetizer, Main Course, Soup

Cuisine: French

Diet: Low Lactose

Servings: People

Calories: 566kcal

Author: Ayla Clulee

Ingredients

For the Soup

½ stick butter (50 grams)
3 ½ oz finely sliced red onion (100 grams)
1 lbs finely sliced yellow onion (450 grams)
1 clove garlic (finely chopped)
3 tablespoon vermouth or sherry
3 tablespoon plain flour
3 cups beef stock
½ oz smoked bacon (15 grams)
2 bay leaves
3 sprigs thyme
¼ teaspoon freshly ground black pepper
salt to taste

For the Garnish

1 baguette
1 clove garlic (cut in half)
1 cup Gruyère cheese (finely grated)
½ cup Parmesan cheese or any hard Italian cheese (finely grated)

US Customary - Metric

Instructions

Caramelize the Onions

To make the soup, start by slicing your onions. Try to slice them finely for perfect and quick caramelization.
Place a Dutch oven or a heavy-based pan on low heat and add the butter.
When the butter melts, add the sliced onions to the pan.
Gently cook the onions until nice and soft, stirring occasionally to avoid them burning. That usually takes around 15 minutes.
When they are soft and translucent, turn the heat up to medium-high to start the caramelization.
Keep stirring the onions to avoid burning them and be patient at that stage. We need nice golden brown color on onions without burning them. Burnt onions will give a bitter taste and unpleasant look to the soup. If the onions aren't caramelized enough, the soup will lack the sweetness coming from the onions.

Build the Soup

When the onions are golden brown and release their sweetness, add the garlic and cook for another minute.
Use vermouth or sherry to deglaze the pan, and then add the flour.
Give it a good stir then deglaze the pan again with some of the beef stock to dissolve all the brown bits stuck to the surface.
Add the whole bacon, bay leaves, thyme, and black pepper along with some more of the beef stock. Only add just enough stock to make a thick soup. You can always add more later if it's too thick at the end of the cooking period.
Bring it to a boil, turn the heat to low, and let it gently simmer for 45 minutes.

Garnish the Soup and Serve

Preheat the grill to 200° C (390° F) and start preparing your garnish while the soup is cooking.
Thinly slice the baguette, rub them with garlic, and place them in the oven for a few minutes until lightly toasted.
When the soup is cooked, remove the whole bacon, bay leaves, and thyme stalks. Check the seasoning and add some salt if needed.
Ladle the soup in individual oven-proof bowls or ramekins.
Put a slice (or two!) of baguettes on top of the soup, top them with your cheese mixture, and place the ramekins in the oven.
Let them under the grill until the cheese is bubbly and slightly golden.
If you don’t have oven-proof individual bowls or ramekins, you can grill the cheesy baguettes separately on a tray and place them on soup ladled in bowls.

Notes

This recipe makes about 6 servings when served as a starter or appetizer.
The vermouth or sherry is optional. Leave it out and use a little extra beef stock instead if you'd rather not cook with alcohol.
Don't have oven-safe bowls? Broil the bread and cheese separately on a baking sheet, then float them on top of the soup just before serving.
Burnt onions will turn the soup bitter, so keep the heat low and be patient while caramelizing. See the Top Tips section above for more on getting this right.
Make ahead: cook the soup up to 3 days in advance and keep it in the fridge without the bread and cheese. Reheat gently on the stove, then add the toppings and broil just before serving.
Store leftover soup (without the bread and cheese) in an airtight container in the fridge for up to 5 days, or freeze for up to 3 months.

Nutrition