Vegetarian French Onion Soup

Suitable for vegetarians. Omit cheese and butter for a vegan version. Serves 4.

French Onion Soup is one of my absolute favourite dishes. The flavours are so deep and complex and the addition of the melted cheese on top turns it into a bowl of complete indulgent deliciousness. It is, in my opinion, the ultimate comfort food.

The only issue is that the soup is made almost exclusively with two ingredients; onions and beef stock. Trying to find a vegetarian French Onion Soup recipe can be frustrating, especially where the instructions are simply to substitute the beef stock for vegetable stock. Most vegetable stock is nothing like beef stock in terms of flavour or colour and so what you end up with is pretty far removed from the French Onion Soup you know and love.

So in putting this recipe together, I set out with the intention of finding a vegetarian replacement for beef stock that does not compromise on flavour. After a bit of research and trial and error, I landed on a mushroom broth recipe that works extremely well. It is meaty, full of umami, and has a subtle funky spiciness that you get from a good beef stock. I have started using this broth in all kinds of soups and stews, and so I have included the recipe separately below.

This soup is not a quick meal. The broth itself takes about 3 hours to make and the soup can take anywhere from 5 to 8 hours. It is definitely a weekend project. However, you are extracting a lot of flavour from only a few ingredients so this is not something you want to rush. Time equals flavour and so a lot of time means a lot of flavour. And on the plus side, most of the time spent is just letting things cook down and simmer. Therefore, I would recommend starting the broth and the soup at the same time. You don't need to add the stock until 3 to 4 hours into the cooking time so it should be ready to use by then.


Mushroom Broth

Ingredients;

• 1 kg mixed mushrooms (I used 500g chestnut, 250g shiitake, and 250g oyster), roughly chopped, 
• 2 yellow onions, chopped in half, skins left on (the onion skins help to give the broth a dark colour), 
• 1 large carrot, roughly chopped, 
• 1 leek, chopped, with green ends removed, 
• 4-6 cloves of garlic, peeled and slightly crushed, 
• 1 tsp smoked paprika, 
• 4-5 sprigs of fresh parsley, 
• 6 sprigs of thyme, 
• 4 sprigs of rosemary, 
• 1 bay leaf, 
• 2 tsp whole black pepper corns, 
• 2 tsp mustard seeds, 
• 5 tbsp tamari or soy sauce, 
• 12 cups water.

Method;

• Place a large pot over medium high heat with 2 tbsp of oil.
• Place the onions, cut side down, into the pot, and let brown for 4-5 minutes.
• Add the garlic, carrot, and leek and cook for another 4-5 minutes or until slightly browned.
• Add all of the mushrooms along with a pinch of salt, to draw out the moisture. Cook down for 3 minutes or until the mushrooms have started to give off some moisture.
• Add the soy sauce and paprika and mix to coat all of the ingredients.
• Add the water along with the parsley, thyme, rosemary, bay leaf, pepper corns, and mustard seeds.
• Bring to a boil and reduce heat to low.
• Let simmer for 2-3 hours or until the broth has developed a dark brown colour and is very flavourful.
• Strain out all of the ingredients and reserve the broth for future use.

French Onion Soup

Ingredients;

• 3 large yellow onion, thinly sliced, 
• 3 large red onions, thinly sliced, 
• 6 shallots, thinly sliced, 
• 2 tbsp butter, 
• 2 tbsp olive oil, 
• 1/2 cup white wine, 
• 1/2 cup dry sherry, 
• 1/4 cup brandy, 
• 8 cups mushroom broth, 
• 6 sprigs of thyme (reserve some leaves for garnish), 
• 1/2 cup grated gruyere cheese per bowl (I added a couple of slices of brie too for additional flavour and texture).

Method;

• Place a large pot over medium heat. Add the oil and butter and wait for the butter to melt.
• Add all the onions to the pot (if you like, you can reserve a handful of onions to add later. That way you get a contrast of textures between the deeply caramelised onions and the less cooked onions).
• Mix to coat all of the onions with the melted butter and oil.
• Cover the pot and reduce heat to low. Let the onions cook down for 2-3 hours, stirring occasionally to make sure they don't burn, until you have a light brown onion mixture that tastes very sweet. It should look like the adjacent picture.
• Add the wine, sherry, and brandy. Let reduce, uncovered, for another hour.
• Add the mushroom stock along with the thyme and any reserved onions. Let simmer, partially covered, for a further 2 hours.
• Season to taste with salt and pepper.
• Serve in a sturdy, oven-safe bowl.
• Optionally, top with a piece of toasted sourdough bread along with half a cup of grated gruyere cheese and a couple slices of brie.
• Place the bowl into an oven preheated to 220c for 5-7 minutes or until the cheese is melted and slightly browned.
• Garnish with a few fresh thyme leaves and serve while hot.