French Onion Soup is one of my favorite comfort foods, but I usually reserve this warm and cozy soup for restaurants because it takes time and patience to make. But I’ve come to realize that although it is a slow process, French Onion Soup is still ridiculously simple and inexpensive, so it’s totally worth the effort. It’s full of sweet caramelized onions, a rich and savory broth, crusty bread, and gooey cheese. You’ve got to make this incredible French Onion Soup recipe on your next day off while you’re relaxing with a movie or folding some laundry. I think you’ll be glad you did!
What is French Onion Soup?
If you’ve never had the pleasure, French Onion Soup is made with sweet caramelized onions, beef broth, and herbs, then topped with a piece of toasted bread and a generous heap of cheese, which are then broiled to perfection. With every spoonful, you get a piece of bread soaked with flavorful broth, melty cheese, and sweet-savory onions. It’s pretty epic.
Ingredients for French Onion Soup
French Onion Soup is deceptively simple. You don’t need much to make the deliciously complex flavors. Here’s what you’ll need to make homemade French Onion Soup:
- Onions: We used yellow onions for this recipe because they’re the perfect mix of sweet and savory flavor, plus they’re very budget-friendly!
- Butter and Oil: The onions are slowly cooked in a mixture of butter and oil as they caramelize. Butter gives the onions extra flavor while oil keeps the mixture from browning too quickly.
- Flour: A little all-purpose flour helps thicken the broth just enough to give it body and not feel watery.
- Beef Broth: Beef broth is the savory base for the soup. The beefy flavor pairs perfectly with the caramelized onions and cheese (think caramelized onion burger!).
- Seasoning: Thyme, bay leaf, pepper, and Worcestershire sauce are used to give the soup even more flavor.
- Bread: French Onion Soup is traditionally topped with a thick slice of bread that soaks up all that delicious broth. We used French bread, but you can use any hearty, crusty bread.
- Cheese: Cheese is melted on top of the bread for a gooey, creamy finish to the soup. Gruyere is traditional, but if you can’t find it at your local store Swiss is equally delicious.
What Else Can I Add to French Onion Soup?
I made this French Onion Soup recipe as simple as possible while still retaining its rich flavor. But if you want to go above and beyond, here are some other ingredients you can add:
Wine – Try deglazing the pot (after adding the flour) with about 1/2 cup of wine before adding the beef broth. You can use either a dry white wine or a red wine, depending on whether you want your soup to have a lighter touch (white wine) or a richer flavor (red wine).
Sweet Onions – I made my soup with your average everyday yellow onions, but if you want a tad more sweetness you can choose a sweet onion instead.
Brandy or Sherry – A couple of tablespoons of brandy or sherry added to your French Onion Soup at the end can brighten the flavors.
Garlic – I didn’t want to muddy the sweet delicate flavor of the onions, but a lot of people do prefer to also add garlic. If adding garlic, mince it up well and sauté it with the caramelized onions for a minute or two just before adding the flour.
Tips for The Best French Onion Soup
If you want your French Onion Soup to have the absolute best flavor, follow these tips:
- Don’t rush through caramelizing the onions. Cook them low and slow until they become dark brown and jammy in texture (see reference photos below). The caramelized onions are what give the soup its rich dark flavor and color, so don’t skimp!
- Use a good quality beef broth. We use Better Than Bouillon to make our beef broth because it’s extremely flavorful and contains a decent amount of salt, which seasons the soup well. Skip watery and bland boxed broths.
- Use good bread. Because the bread is floating on top of the soup you need to make sure it can hold up to being soaked in liquid. Opt for the heartiest bakery bread you can find.
- Don’t use pre-shredded cheese. Pre-shredded cheese is often coated in cellulose which prevents it from melting as smoothly as block cheese that is grated by hand. For maximum cheesy goodness, shred your own cheese!
How to Store Leftovers
Leftover French Onion Soup will stay good in the refrigerator for 4-5 days, or it can be frozen for about three months. Store the soup without the bread and cheese, and add them only after reheating. The soup can be reheated in the microwave or in a saucepot on the stove over medium-low heat, stirring often.
Love caramelized onions? Try our French Onion Dip recipe!
French Onion Soup
- 2 Tbsp olive oil ($0.32)
- 3 lbs. yellow onions ($1.19)
- 2 Tbsp butter ($0.28)
- 3 Tbsp flour ($0.03)
- 6 cups beef broth* ($0.78)
- 1/2 tsp dried thyme ($0.05)
- 1 bay leaf ($0.15)
- 1/4 tsp freshly cracked black pepper ($0.02)
- 1 Tbsp Worcestershire sauce ($0.02)
- 5 slices French bread ($1.00)
- 1 cup shredded Swiss or Gruyere cheese ($1.00)
- Slice the onions into ¼-inch thick slices. Add the sliced onions to a large soup pot with olive oil. Cook the onions over medium heat, stirring occasionally. When the onions begin to get a little bit of golden brown color (after about 30-45 minutes), add the butter.
- Continue to cook over medium heat, stirring occasionally until the onions are deeply caramelized (the color of an old penny). This should take about an hour total. If needed, add a couple tablespoons of water to dissolve any browned bits off the bottom to prevent them from burning while the onions continue to cook.
- Once the onions are deep brown and jammy in texture, add the flour. Stir and cook the flour with the caramelized onions for about two minutes more. The flour helps thicken the broth slightly, giving it body.
- Add the beef broth to the pot and stir to dissolve any browned bits off the bottom of the pot. Also add the thyme, bay leaf, pepper, and Worcestershire sauce. Bring the soup up to a simmer, then allow it to simmer for about a half hour. If using a low sodium broth, make sure to taste the soup after simmering and add salt to taste.
- Toward the end of the simmer time, preheat the oven's broiler. Place the bread slices on a baking sheet and place them in the oven on the middle rack. Broil for a few minutes on each side, or just until they are barely golden brown (they will broil more later).
- If you do not have oven safe bowls, top each slice of bread with shredded cheese, then return them to the oven and continue to broil until the cheese is melted and bubbly. Broiling time will vary with each oven, so make sure to watch them closely. This should only take a few minutes. Place one piece of toasted bread with melted cheese on top of each bowl of soup just before serving.
- If you do have oven safe bowls, portion your soup into the bowls, top each one with a piece of lightly toasted bread, then some of the shredded cheese. Place the bowls back on the baking sheet and place everything back in the oven under the broiler. Broil for just a few minutes or until the cheese is melted and bubbly. Serve hot!
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Love cozy soups? Check out all of our Budget-Friendly Soup Recipes!
How to Make French Onion Soup – Step by Step Photos
Begin by slicing 3 lbs. yellow onions into thin slices (about ¼-inch thick). Add the sliced onions to a large soup pot with 2 Tbsp olive oil. Cook the onions over medium heat, stirring occasionally.
When the onions begin to get a little golden color (after about 30-45 minutes) add 2 Tbsp butter. Continue to cook over medium heat, stirring occasionally.
The goal is to keep cooking until the onions become deep brown in color and have a jammy texture. If the bottom of the pot begins to brown faster than the onions, just add a couple tablespoons of water to dissolve the browned bits off the bottom and continue to cook. Do not stop when the onions are the color in the photo above. There is still a ways to go!
When the onions are the color of an old penny (see photo above), add 3 Tbsp flour and continue to cook and stir for about two minutes. The flour helps thicken the soup very slightly, just giving it a little extra body.
Finally, add six cups of beef broth to the pot. Stir to dissolve any browned bits off the bottom.
Also add ½ tsp dried thyme, one bay leaf, ¼ tsp freshly cracked pepper, and 1 Tbsp Worcestershire sauce. Bring the soup up to a simmer and let it continue to simmer for about 30 minutes. If you’re using a lower sodium broth, you’ll want to taste the soup and add salt to taste after it simmers.
Toward the end of the simmer time, begin to prepare the cheese toast. Preheat the oven’s broiler. Place slices of French bread on a baking sheet (I only had four soup bowls, so I’m only toasting four pieces right now, but the soup makes about 5 servings). Broil the bread for a few minutes on each side or just until it’s lightly golden brown. It will broil more later with the cheese.
If you have oven-safe bowls, portion the French Onion Soup into the bowls. If you do not have oven-safe bowls, pile the shredded cheese right onto the toasted bread on the baking sheet, then broil for a few minutes more to melt the cheese. Top each bowl of soup with a cheesy bread slice.
If you do have oven-safe bowls, place the bowls on the baking sheet and add a piece of toasted bread to each bowl, then top with shredded Swiss cheese or Gruyere.
Return the baking sheet with the bowls of soup to the oven and broil for a few minutes more, or until the cheese is melted and the bread is toasty. Every broiler is a little different, and they cook quickly, so keep an eye on them!