This Vegetarian French Onion Soup is a celebration of the onion. Instead of beef broth, which masks the onion, the slowly caramelized onions make their own sweet, deeply flavorful broth as they cook.
Do you ever have “ah ha” moments?
Moments where suddenly, everything makes sense, and your world will never be the same again?
I had one of those moments recently– about onions.
Don’t stop reading, guys! It’s good– I swear!
Specifically, my “the skies opened and everything was clear” moment was about how to make a vegetarian French Onion Soup.
Isn’t French Onion Soup already vegetarian?
Typically, onion soup is made with beef broth.
And vegetarian versions of onion soup are all over the place, but they often try really hard to replicate the flavor of beef broth by adding lots of extras to the broth.
And guys, they’re never as good as the classic.
Recently though, I was reading Michael Ruhlman’s book Rhulman’s Twenty, and he argues that French Onion Soup was originally a vegetarian peasants’ dish.
Since peasants wouldn’t have always had access to pricey bone broth, they would’ve made the soup without it.
I wasn’t convinced yet, but in theory, I loved it. So I tried it.
It was SO GOOD!
The broth you get from simply using well-caramelized onions, hot water, and a little wine, is INCREDIBLE.
It’s so incredibly delicious, that when I tasted it– I immediately threw away all my other vegetarian French onion soup recipes, because it was one of the best things I’ve ever eaten.
Here’s how I make my onion soup now.
What Kind of Onions Should I Use?
First things first– let’s talk onions. You don’t need special, hard to find, extra expensive onions– yellow onions will work just fine.
Grab about eight (yes that’s right– eight) onions.
What Kind of Bread Should I Buy?
A French baguette is perfect for this French soup.
Traditionally, you’d just slice the baguette, but I find this soup is easier to eat when I cut the bread up into small cubes.
What Kind of Cheese Should I Buy?
Traditionally, French onion soup is made with Gruyère, but I also love it with sharp white cheddar cheese.
Use whatever cheese you love best.
What Kind of Pot Should I Cook vegetarian french onion soup In?
If possible, use an enameled cast iron Dutch oven.
For one thing, the heavier your pot is, the more evenly it’s going to distribute the heat to your food. For caramelizing onions, this matters.
Another reason to pick an enameled cast iron pot for this soup is because we’re going to “deglaze.”
In other words– when the onions finish cooking, they’re going to leave caramelized bits stuck to the bottom of the pot.
We’re going to crank the heat up, and pour wine in the pot to pull all that yumminess off the pot and back into the onions.
Enameled cast iron doesn’t have to be expensive. I use a Lodge Enameled Cast Iron Dutch Oven.
Can I Use a Stainless Steel Pot instead?
If you don’t have an enamel cast iron pot, don’t cry!
Unless you’re crying because of the onions– if that’s the problem, see the tips below!
Stainless steel will work well while caramelizing– you just have to watch the onions a little bit more closely than with enameled cast iron.
Stainless steel also works well for deglazing, but in my opinion– enamel works even better, because the caramelized bits are less likely to burn.
Quick Tip: If you want to use a regular, non-enameled cast iron pot– be careful– deglazing with wine can pull the seasoning off the pan.
How Big Should My Soup Pot Be?
It needs to be big.
7 quarts is ideal for 8 onions– if your pot is smaller, try breaking the onions up into two pots.
The wider the base of your pot, and the higher your heat, the faster they’ll caramelize.
How Long Does it Take To Caramelize Onions?
To make an onion soup featuring the deeply complex flavors of caramelized onions– you’re going to have to caramelize them very well. Peel them, slice them, and get started.
Budget anywhere from 2-5 hours to caramelize them.
Avoid turning the heat higher than medium-low, and remember that the lower the heat, the sweeter the results.
Quick Tip: For a faster cook-time– caramelize your onions ahead of time and freeze them!
Do I Need Special Oven-Safe Soup Bowls for vegetarian french onion soup?
If you’ve got them– great! Set them on a baking sheet, and ladle this vegetarian French Onion Soup into your oven-safe bowls.
Add some diced cubes of crusty bread to the soup, and top it all off by shredding as much cheese as your little heart desires.
Set the baking tray carefully in the oven, and cook until the cheese is golden and bubbly. If you don’t have oven-safe bowls, just brown the cheesy bread separately on a baking sheet, and then plop it into your soup.
I like to top my soup off with some diced green onions, but I’m just a little crazy like that.
Onion soup, topped with onion? Why not!
Onion Cutting Tips
If you haven’t figured it out, you’ll be cutting up a lot of onions to make this soup. If cutting up onions makes your eyes water badly, try these few tricks:
- Don’t wear glasses if you don’t have to!! Obviously I’m not advocating blindly cutting your onions, but if you are able to wear contacts, I’ve found this helps tremendously. The fumes get caught between the glasses and your eyes.
- The husband swears using a serrated knife makes the onion fumes worse. Make sure you’re using a sharp, smooth-bladed knife.
- For more tips on how to keep the onion fumes from burning your eyes, check out this article at The Kitchn.
Want more FRENCH FOOD? Try these:
Vegetarian French Onion Soup
- 2 tablespoon butter (or sub olive oil)
- 8 yellow onions, thinly sliced
- 1 teaspoon sea salt, plus more to taste
- 3 bay leaves
- ½ cup dry white wine
- 2 sprigs rosemary, destemmed + (optionally) roughly chopped I use ~2" long sprigs of rosemary
- ½ French loaf, cubed (~2 cups)
- 2 ounces Gruyère or sharp white cheddar cheese, freshly shredded (use more or less as desired)
- diced green onion to garnish (optional)
- In a large heavy bottom pot, melt butter over medium heat. Add onions, salt, and bay leaves. Cover pot, and cook over medium-high for 4-5 minutes, until they begin to look translucent and start releasing water.
- Remove lid, and cook onions over low (or medium-low) until they caramelize. This will take 2-5 hours, depending on the size of your pot and the temperature used. The onions can be left alone and checked on about once an hour, except at the beginning and end of the caramelizing process. Tip– this can be done ahead of time, and the onions frozen until you're ready to use them.
- When onions have reduced and are an amber color, you’re ready. Increase the heat to medium-high and add the wine. Allow the wine to boil down for 3-4 minutes.
- Add 5 cups of hot water and the rosemary, and bring to a boil. Then, reduce to a simmer. Taste soup. If you prefer a milder flavor, add another cup of hot water. If desired, add another splash of wine. If the soup is too bland, add extra salt. Remove the bay leaves.
- Turn on oven broiler.
If using oven-safe bowls:
- Ladle soup into bowls, then set bread into soup. Pile desired amount of cheese over bread. Set bowls onto a baking tray, and set under broiler 1-2 minutes until cheese has melted and is golden.
Garnish soup with fresh herbs (optional), and serve immediately.
If NOT using oven-safe bowls:
- Lay bread cubes on baking sheet and top with cheese. Set in oven under broiler for 1-2 minutes, until cheese has melted and is golden. Ladle soup into bowls, and set cheese bread on soup. Garnish soup with fresh herbs (optional), and serve immediately.