French onion soup is one of those magical foods. It’s sweet and savory and filled with all that umami goodness. And it is really easy to make and doesn’t have to take forever!
I wanted to put the formula/recipe first and then go into the whys of the method and ingredients. So keep scrolling to learn more about the method!
French Onion Soup Formula
- 1 large onion per serving (increase to two onions per serving if using small or medium onions)
- 1 tbsp fat for every onion (butter, olive oil, coconut oil etc.. or a combination of any type)
- 1 sprig of thyme per onion- all tied up in one bundle with kitchen string
- 1-2 cups beef broth per onion (or veggie broth for a vegan/vegetarian option)
- Salt to taste
- Optional: Wine to deglaze pan- preferably red
- Optional: Balsamic vinegar to taste
- Slice onions using this method.
- Melt fat in a wide, deep pan on medium heat.
- Add onions and thyme bundle and a chef pinch of salt (using 3-4 fingers to pinch).
- Cook on medium/medium high heat stirring occasionally. Rotate the pan if you notice any hot spots.
- Once onions have reached a deep caramel brown color, deglaze with enough wine to cover the bottom of the pan. Then let the alcohol burn off and the wine reduce until there is about a tablespoon of wine left.
- Add beef broth and let soup simmer for 10 minutes.
- Finish with balsamic vinegar to taste.
- Remember to taste it! Look for saltiness (read more about that here) and acidity. Adjust as necessary.
- Finish with a piece of toasted bread with melted gruyere cheese on top. Enjoy!
Wide and Deep Pan
I recommend using a wide pan with tall sides to help aid the caramelization process. The more surface area the better because when caramelizing onions the steam needs to escape for the caramelization to occur. A wide pan will do that more efficiently than a tall pot. A tall pot is meant to help retain moisture. Which is why it is good for boiling water and other soups where you don’t want a lot of reduction happening.
Caramelization occurs when sugar reaches a high temperature. Think making a caramel sauce. Caramelization can only occur when there is no or very little water present. So, salt your onions to draw out moisture and use a wide pan with tall sides to allow steam to easily escape.
When it comes to knowing if your onions are caramelized enough don’t be afraid to go darker. You know you’e gone too far if the onions turn black and have burned. You will also be able to smell that something has burned. That burnt taste is bitter and unpleasant and will overpower all flavors in your soup.
If you notice hot spots in your pan (a particular spot where the pan and onions are getting more color) rotate your pan and add a very small amount of water to that spot to help prevent burning.
My favorite onion to use is a yellow onion. They are easy to find, affordable and caramelize really well. The yellow onion is like the all purpose flour of the onion world. You can eat it raw and it cooks really well.
You could also use a sweet onion or a Vidalia. A vidalia is a type of sweet onion that is usually harder to find and more expensive. But some people swear by using Vidalias for french onion soup.
The only onion to stay away from is a red onion only because red onions take on a sad, gray color when cooked. Which is not appetizing.
Salt the onions at the beginning of the process. The salt helps draw out moisture from the onions. The onions can’t caramelize until enough moisture has cooked out. It also helps season the onions so they are the most flavorful they can be in the final product.
Watch this video here to learn how to properly slice onions.
Tie thyme in some kitchen string to infuse soups, stews, and sauces with thyme without having to chop it! I like to tie my thyme sprigs with two or three pieces of kitchen string.
I do this because I hate chopping thyme! It takes too much time with little payoff. Tying it into a bundle works great for soups and stews because you get an infusion of thyme flavor without all the work. Also some of the thyme leaves fall off into the soup anyway. It’s a win win all around.
The reason I tie it up with kitchen string is so that I can pick it out a lot easier. Like a bay leaf. Tying the thyme in multiple places ensures that is stays in one bundle and doesn’t fall apart.
I highly recommend using butter in French onions soup. Onions cooking in butter is one of my favorite smells in the kitchen. You can’t beat it. I will still add a little bit of an olive oil/canola oil blend (you can read more about that here). The butter adds great flavor and the olive oil/canola oil blend helps increase the smoke point. So I use about 2/3 butter and 1/3 of the 50/50 blend.
In an ideal world French onion soup would be made with a rich home made beef broth. But I am a realist. I hardly ever make beef broth because I never have beef bones readily available. I love using “Better than Bouillon”. I think it has a great taste for what it is and it goes a long way.
An optional step but I love the flavor that wine gives to a French onion soup. I think a red wine works great. But I’ll be honest, I use whatever I have in the fridge. In culinary school we used boxed wines for everything. It is a great option for cooking. They last a long time and you don’t need to fuss with opening a bottle.
I use the wine to deglaze the pan. Wine is a great liquid to deglaze a pan with because it adds great flavor and a little bit of acidity. The beef broth will also deglaze the pan, any liquid will really. But keep in mind that whatever liquid you add will add flavor to the final product so pick one that enhances the flavor of the dish. And stay away from really salty or really sweet liquids.
But please do not use cooking wine. It has salt added to it and a terrible flavor. Just don’t.
Adding a little bit of balsamic vinegar at the end of the cooking process introduces another flavor profile to counter balance the richness from the beef broth. When seasoning food keep in mind that salt, sugar, and acid can work together to produce a delicious well-rounded flavor profile.
The acid in Balsamic vinegar cuts through the richness of the beef broth and the sweetness pairs well with the sweetness of the onions.
Bread and Gruyere Cheese
Traditionally French onion soup is topped with a slice of rustic bread and Gruyere cheese and then broiled to melt and toast the cheese on top. This adds a nice contrast in texture with the rustic bread and a buttery taste from the cheese.
I personally like to broil the bread and cheese separately and then serve the bread on the side. I like maintaining the crispy texture of the bread. But again it is traditionally served on top of the soup. Be sure that whatever bowls you use are oven safe if you broil the bread and cheese on top of the soup.
So there you have it! I am interested to know if you like the formula style of a recipe vs. a traditional recipe post. I want to empower my readers to step away from recipes and understand the method behind recipes. And as always let me know if you have any questions in the comments below!
Equipment used in this post
A classic for a reason. I personally love the weight of this knife and the bolster. A solid knife that is a work horse in the kitchen. Click here to view on Amazon.
All-clad sauté pan
I love All-Clad pans. The D3 stainless steel collections is my personal favorite line they carry. This pan is perfect for soup, frying, sautéing, you name it. It’s a very versatile pan and worth having in your collection. Click here to view on Amazon.
EPICUREAN CUTTING BOARD
A great, durable cutting board made out of a nonporous, composite material. Safe to cut meat on and dishwasher safe. Just a solid, very well made cutting board. Click here to view on Amazon.
A simple tool with so many functions. In knife skills it is perfect for scooping your food off your cutting board. Click here to view on Amazon.