Classic French onion soup is a staple item at French bistros, and for good reason. Caramelized onions are cooked in delicious beef broth then topped with lots of cheese and crusty French bread until the cheese is bubbly and the bread crisp.
French Onion Soup
French onion soup was one of the first recipes I posted on the blog back when I’m pretty sure my mom and dad were the only ones who were following along here. That doesn’t mean, however, that this recipe hasn’t been made since then.
In fact, French onion soup is one of my favorite soups to make, and I make it several times, year-round. I have pretty much used the same recipe since I first made it, with some minor tweaks. I thought I’d refresh this blog post so that it reflects exactly how I make my French onion soup today.
How to Make French Onion Soup
I’m a big fan of onions, so it’s really no surprise that I love this soup so much. Unlike butternut squash soup, however, French onion soup can’t be whipped up in 20 minutes.
Because onions are one of the few ingredients in this soup, it’s very important to give them time to fully caramelize. The caramelization process is what gives this soup the fantastic onion flavor. If you pour your broth in before the onions have caramelized, you’ll end up with bland soup.
But what this French onion soup demands in patience it lacks in effort. French onion soup is truly a simple soup to make. The onions are softened for 15 minutes before they’re seasoned and left to caramelize for another 45 minutes. After that, beef broth is added and the soup is warmed until it’s bubbling and hot.
The soup is simply dispersed in oven-safe bowls (similar here), then topped with slices of French baguette and cheese.
You can use any variety of cheese that melts well, but I personally love gruyere cheese or a mix of cheddar and gruyere for varying flavor. The gruyere tends to be salty, which the cheddar adds a bit of sharpness that I enjoy.
The French onion soup is baked until the bread is extra crisp and all that glorious cheese is bubbling and melted. In each spoonful of soup, you get broth, a chunk of bread, and melted cheese – a delicious combination that you don’t find in other soups.
French Onion Soup
A classic French bistro soup made with caramelized onions, beef broth, French bread croutons, and melted cheese.
- 2 extra large onions (8 cups sliced onions), sliced thinly into crescent shapes
- 1 1/2 tbsp unsalted butter (21 grams)
- 1 tbsp oil (14 grams)
- 1/2 tsp salt (2.8 grams)
- 1/8 tsp sugar (<1 gram)
- 1 1/2 tbsp all-purpose flour (~10 grams)
- 4 cups low-sodium beef broth (907 grams)
- ground pepper and salt to taste
- crusty French bread sliced
- 4 oz gruyere cheese for the top or gruyere-cheddar mix
Melt butter with oil over low heat in a dutch oven or large pot. Add the onion slices into the pot and cover for 15 minutes.
Slice your bread into 1/2 inch slices and toast them. Temporarily set aside.
Raise the stove heat slightly and stir in 1/2 tsp of salt and 1/8 tsp of sugar. Cook, uncovered, for another 40 to 45 minutes until onions have caramelized, stirring occasionally throughout the duration. Note: Do not rush this step as it is essential for developing the onion flavor.
Sprinkle (1 1/2 tbsp) flour into the pot, stir, and cook for another 3 minutes. Slowly stream the broth into the pot, stirring as your pour. Season with a pinch of salt and pepper, to your taste. Just don't make the soup too salty if you're using a salty cheese like gruyere. Cook for another 20 minutes until simmering and hot. Preheat your oven to 350°F.
Once the soup is ready, divide the soup among 4 oven-safe bowls. Place 4 or 5 baguette slices into each bowl. Then top each bowl with grated cheese (about 1/4 cup of grated cheese per bowl). Bake until cheese completely melts.
This recipe will yield 4 servings that are perfect for soup as an appetizer. If you want to serve the soup as a main course, double the recipe ingredients.