With its rich and filling flavor, French Onion Soup is classic comfort food. It’s made with a delicious broth made of caramelized onions, herbs, toasted bread, but the melted cheese topping is the real star of this restaurant style soup. This authentic recipe includes step by step instructions with an emphasis on simplicity for the perfect soup!
Who could ever resist the robust flavor of an authentic French Onion Soup? Of course, the best part is the crusty crouton topped with melted cheese!
This recipe has been in my family for many, many years and I have developed some adaptations, but I always come back to the classic base. The beauty of this soup lies in its simplicity. Do it right, and you will have the perfect comforting bowl of delicious soup!
Why You Should Make This Recipe
- The most important characteristic of a good French onion soup is properly caramelized onions. Caramelizing is a chemical process that occurs when the sugars in the onions reach a certain temperature and they become sweeter and darker in color.
- The simplicity in high quality ingredients make for the perfect base that brings forth every note. Nothing extra to cover that authentic taste.
- This is the recipe searched for in restaurants in the United States. It is mellow and buttery with commonly found staples.
- I have included several options to customize it for fun experimentation!
Ingredients and Notes
Here is an overview of the ingredients you will need to make this recipe, as well as notes like substitutions. Using high quality ingredients is very important for a proper flavor profile.
Yellow Onions: My mother has sworn by “cheap ol’ yellow onions” my whole life and she’s right on with that advice. Vidalias are too sweet, and red onions are too mild.
Cooking Sherry: Sherry cooking wine has a sweet aroma and golden color. Its taste is close to a dry drinking sherry with a slightly nutty flavor. You can use a drinking sherry, which will have less salt and may taste a little different. If you do not have sherry on hand, you can use a dry white wine, but it will slightly change the flavor profile.
Cheese: I find that a good swiss is the best for a creamy, melty flavor. You can also experiment with Gruyere, Emmental, or add some parmesan along with the swiss.
Beef Stock: Stock is made with cleaned bones, unlike broth. It gives the soup its signature dark brown color and robust flavor. While I would encourage a homemade beef broth, a high-quality store-bought stock works well in a pinch.
Beef Base: Rather than using salt, this is my favorite addition for seasoning.
French Bread: French Bread is the traditional and best option. However, you can substitute a crusty bread that won’t become too soggy in water such as ciabatta or a crusty sourdough.
Seasonings: Fresh thyme and minced garlic round out the caramelized onions and cheese.
Butter and Oil: Butter is best for caramelizing the onions, while the oil helps the croutons crisp up nicely.
Soup Crock: Oven and Microwave safe, these are great to serve and melt the cheese on top directly in the oven.
How To Make French Onion Soup
The full recipe is in the recipe card at the bottom of this post, but I include this section for my own tips and visual guide for preparing the ultimate soup making experience.
- Caramelize the Onions: Low heat, nice and slow is the way to go. This is the step that makes the flavor! Caramelizing is a chemical process that occurs when the sugars in the onions reach a certain temperature and they become sweeter and darker in color. This step takes at least 25 minutes, but the caramelization process turns the onions sweet and makes the broth pop.
Pro Tip: The onions should be a rich, golden brown rather than the color of dark chocolate or the beef broth. The sweet, deep flavor that we are trying to achieve is a better indicator than the color. If the onions aren’t turning, try adding a teaspoon of sugar to get the caramelization process going.
2. Wine and Seasonings: I prefer sherry for its nuttiness and sweet complexity. Most varieties of wine work well since this soup is very forgiving. If you have leftover red, use that. Sherry, cognac, and port wine are also great options!
3. Simmer: A generous simmer time allows the flavors to meld and gives it a fuller bodied flavor. The broth should have a transparent dark caramel color since it is mostly beef broth.
Make the Croutons: Brush each side of the bread slices with a bit of olive oil and bake for 10-15 minutes in the oven on each side until the side starts to turn golden and hardened.
Tip: I usually make extra croutons or just serve with an additional loaf of french bread for dipping. I don’t know about you, but I love to sop up every bit of the juice and onions.
Broiling the Cheese: Ladle the soup into oven safe bowls and top with bread and cheese. You can shred or slice the cheese. Broil until golden. If you don’t have oven safe bowls, you can broil the cheese topped bread and then place on top of the soup.
Make It Your Own
- Add ¼ cup Cognac with the Sherry
- Add ¼ cup Port wine instead of the Sherry
- Substitute Gruyere Cheese or Aged Havarti
- Add a bit of freshly shredded Parmesan
- Blond French Onion: 1 cup of heavy cream to the broth
What to Serve with French Onion Soup
There are lot of great options that go with French onion soup. If you are serving the soup as an appetizer, these dishes are excellent entrees:
If you are looking for something a little lighter, artisan sandwiches and salads are a great option like:
Grilled chicken pesto paninis
Bacon Turkey sandwiches on toasted wheat bread
Leftovers and Storage
Store: Leftovers are amazing! Allow soup to completely cool and store in an airtight container in the refrigerator. It is good for 4-5 days at least.
Make Ahead: You can absolutely make the soup base ahead of time. As with most soups, the flavors meld together and get even yummier with a little time. They should not be assembled with the bread and cheese till just before serving for the best result. You can pre-slice your toppings to save a little time and store them in a Ziploc till you’re ready to assemble your bowls.
Reheat: This recipe keeps and reheats amazingly well on both the stovetop and the microwave.
- Stovetop: Heat soup in appropriately sized saucepan or pot over medium heat for 5-8 minutes until hot.
- Microwave: You can also reheat individual servings in the microwave by transferring to a microwave safe bowl and microwaving for 60-90 seconds. Add crouton and cheese topping and continue to microwave at 30 second intervals until heated and melted thoroughly.
Freeze: You can freeze the soup without the cheese or crouton topping. Let soup cool completely. Add soup and broth to freezer safe containers or bags. Freeze for up to 3 months. When ready to eat, let soup defrost in the refrigerator overnight.
Love Hearty Soups? Check these out:
- Creamy Sausage and Kale Soup
- Chicken and Wild Rice Soup
- Cabbage Beef Soup
- Broccoli Cheese Soup with Real Cheese
The best advice about making French onion soup is to use the right onions. The best onions are the plain ol’ yellow cooking onions. I once tried to get fancy with Vidalia onions and it completely changes the authentic taste.
French Bread is the traditional and best option. However, you can use any kind of crusty bread that won’t become too soggy in water such as ciabatta or a crusty sourdough.
The traditional cheese is a good quality gruyere cheese. It is a smooth-melting type of Swiss cheese that’s made from whole cow’s milk. I find it to be sharper and more flavorful than American style swiss cheese.
However, most restaurants use plain ‘ol swiss cheese or provolone because it is easily melted and milder in flavor than gruyere.
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French Onion Soup
- 2 tablespoon Olive Oil
- 1 tablespoon Butter
- 3 lbs Yellow Onions – thinly sliced
- ¼ cup Cooking Sherry
- 2 teaspoon Fresh Thyme about 2-3 sprigs
- 1 teaspoon Minced Garlic 2 cloves
- 6 cups Beef Stock
- 1 teaspoon Beef Base
- 8 slices French Bread
- Salt and Pepper to Taste
- Swiss Cheese, sliced or grated Gruyere, Havarti, and Emmental can also be used
- Melt butter and olive oil in a large pot over medium heat. Add onions and sprinkle with salt and pepper. Cook onions until translucent and soft. Turn down heat to med-low and cook until onions are thoroughly caramelized, about 20-30 minutes. Onions should be a golden brown rather than a deep, dark chocolate color.
- Add sherry for 30 seconds and stir to deglaze the pot. Add fresh thyme to taste and more ground pepper, if desired.
- Pour in beef stock and add beef base. Heat to simmer. Cover and reduce heat to low. Simmer for 30 minutes.
- Heat oven to 325 degrees F. Brush each side of the bread slices with a bit of olive oil and place on baking sheet. Cook the slices for 10-15 minutes in the oven on each side until the side starts to turn golden and is hardened.
- Turn heat on oven to broil. Pour the soup into oven safe bowls or ramekins. Top with bread and cover entirely with cheese. Place bowls on a cookie sheet and place under broiler until cheese melts and is bubbly. It only takes a few minutes so watch carefully. *See note if you do not have oven safe bowls.
- If you do not have oven safe bowls or soup crocks, place the toasted bread on a cookie sheet and cover with cheese. Broil the cheese covered bread until golden and bubbly. Place the cheesy croutons on top of the soup.
- The onions should be a rich, golden brown rather than the color of dark chocolate or the beef broth. The sweet, deep flavor that we are trying to achieve is a better indicator than the color. If the onions aren’t turning, try adding a teaspoon of sugar to get the caramelization process going.