I have been craving a proper French Onion soup like the ones I had in Paris 2 years ago. Where the onions are caramelized to rib-sticking unctuousness. I wanted the bread on top of my soup to be thick, soak up the liquid, and so heavily laden with Gruyere that when grilled, it bubbles over the side.
So I made this delicious soup using one of my first two loaves of sourdough bread after nurturing a starter since the beginning of lockdown. All the key elements are in place. This is my to-date best French Onion soup recipe and I cooked part of it in my Instant Pot to speed it up, but you can just as easily let it simmer on the stovetop.
I used two cookbooks as my inspiration for this recipe. The first is Melissa Clark’s Dinner in an Instant and Chad Robertson’s Tartine Bread. The latter is a baking bible for the making of sourdough and a selection of recipes from the famous San Francisco bakery with the same name.
I adjusted the quantities of ingredients from Melissa and used less stock (to keep it more oniony), added more onion (for obvious reasons), more sherry (because this soup needs a decent hit of booze), and a little more fat to get things going at the start.
The Tartine recipe used cream which I loved the sound of, and they added it at the start allowing the Maillard reaction to really set in and get the milk proteins to caramelize. I was a little more cautious with this and added the cream later on, but next time I might allow this to cook a little longer.
When it comes to soup especially one like French onion soup where there are few ingredients, the quality of the stock is important. I was lucky I had frozen farm bone broth and chicken stock from Terra Madre on hand and I loved the combination of beef and chicken here. I would suggest using either chicken or beef stock (or a combination of the two) as it adds a level of richness to this soup.
If you are vegetarian then use a really good quality vegetable stock obviously. If you can get your hands on fresh or frozen stock then all the better and for me, it’s worth going out of the way to source these ingredients as this is not a soup you would make every day.
You can see my list of the best food shops in Cape Town to source suppliers, but off the top of my head, Giovanni’s in Greenpoint, Sans in Sea Point, The Olive Branch Deli in Town, Farmer Angus at Spier, Son of a Butcher in Sea Point & OZCFM, Buyfrsh online deli & Terra Madre in Elgin (online).
More recipes you might like in an Instant Pot:
This recipe makes enough for 2 big bowls of French Onion Soup so double up if you want to make more.
A very delicious French onion soup recipe
- 2 Tbsp olive oil
- 3 Tbsp butter
- 3 large white onions cut to about 3-4mm/ 1/8th inch thick rounds you can slice these in a food processor to make it easier or on a mandolin
- 1 large sprig of Thyme
- 1 tsp flour
- ¼ cup pale dry sherry you could use ½ cup dry white wine instead
- ½ cup cream
- 750 ml good quality chicken stock or bone broth or half beef and half chicken
- Salt & white pepper I love white pepper here
- 2 thick slices of sourdough or one large slice cut in half it's important to use a sturdy bread here
- 1 clove garlic optional
- ¾ - 1 cup grated Gruyere cheese or a strong local hard cheese such as Dalewood Fromage Hugeonot
- Heat the butter and olive oil in a medium-large heavy-based pot and sauté the onion with the thyme for about 10 minutes.
- Add the flour, season well with salt & pepper and cook for a minute.
- Add the sherry to deglaze the pan and cook for a further 1 - 2 minutes.
- Add the cream and allow this to cook for about 4 – 5 minutes until it's really thick and most of the liquid has cooked off.
- Add 1 cup of stock and cook for about 2 minutes once again scraping down the pot.
- To cook in an Instant Pot: Add this mix to the bowl of the Instant pot with the remaining 500ml of stock and cook on high for 10 minutes. Release the pressure manually. Remove the thyme stalk.
- To cook on the stovetop: add the remaining 500ml of stock to the pot and carry on cooking this over low heat for about 30 minutes. Remove the thyme stalk.
- When you are ready to serve, preheat your ovens grill/ broiler. Place the bread on a baking sheet and toast on either side for about 2 – 3 minutes until it is a light golden colour. Remove and rub the garlic clove over the toast (optional).
- Dish up the soup in 2 ovenproof dishes to just below the rim. Place a slice of toast on each soup and then top with the grated cheese.
- Place this in the oven about 1/3 of the way down (so not directly under the grill) and grill until the cheese is golden and bubbling and serve. If your oven has a fan and grill setting you can use this combination to keep the soup piping hot.