Slow Cooker French Onion Soup takes all the work out of stirring and caramelizing the onions in this cheese toast topped French soup.
Slow Cooker French Onion Soup
By Sue Lau | Palatable Pastime
Slow Cooker French Onion Soup is my recipe of the day with the blogging group “From Our Dinner Table”. We get together once per week to post on a variety of topics.
Julia Child Inspired Recipes
This week’s topic is Julia Child inspired recipes.
While Julia Child did not post recipes for the slow cooker or crockpot, she was known for her Soupe à l’oignon Gratinée, or French Onion soup.
It is essentially a caramelized onion soup with wine and herbs, topped with a delicious cheese toast which is broiled right on top of the soup. The bread soaks up the delicious broth and makes the soup hearty enough to be a light meal.
The Ease of a Slow Cooker
Of course, proper caramelization of the onions takes a lot of time and stirring, which can also be worked out by using the crockpot, as I have done here.
Much of the rest of the recipe is the same, as it goes from crockpot to stove for a brief time. Most of the reason for that is that I do the cooking in two stages, one day to cook the onions down, then the next day is just a brief heat.
Doing it on the stovetop brings the roux up to temp quickly and gets the job done fast. However, you can heat it on high and wait for the soup to thicken slightly. If you start from cold onions though, this may take awhile.
Time Saving Two-Step
Besides saving time this way, since once the onions are ready, it is just minutes away, you can also choose to keep the cooked onions in the fridge for several days. This is helpful around the holidays when you want to get some cooking done ahead.
The cheese toast is broiled right on top so use a heatproof crock for the soup. If you don’t have that, just bake up cheese toast in the oven and serve it on the side.
I would suggest doing that anyway for children since a hot bowl could be an issue. You can also omit the booze in the cooking. It does take some of the good flavor away, but understandably a must for children and those avoiding alcohol in food.
Any good melting cheese is great for the toast- I used a fondue blend, but cheese such as Swiss, provolone, mozzarella and cheddar are all good choices. Choose the one you like.
Julia Child Inspired Recipes
- Beurres Composés – Cold Flavored Butters by Karen’s Kitchen Stories
- Cheese Puffs by That Recipe
- Coq Au Vin by Making Miracles
- Easiest Pommes Dauphinoise (Scalloped Potatoes) by Art of Natural Living
- Eggplant Pizzas by A Day in the Life on the Farm
- Organic Ratatouille Lasagna by A Kitchen Hoor’s Adventures
- Slow Cooker French Onion Soup by Palatable Pastime (You are Here!)
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Slow Cooker French Onion Soup
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Slow Cooker French Onion Soup

Slow Cooker French Onion Soup
Equipment
- slow cooker
Ingredients
Slow Cooker:
- 2 pounds onions sliced
- 3 tablespoons melted butter
- 1 teaspoon each salt and black pepper
Finishing:
- 1/2 cup all-purpose flour
- 6 cups beef stock
- 1/4 cup dry white wine
- 2 tablespoons cognac
- 1/2 teaspoon rubbed sage
- 1/4 teaspoon ground bay
- 4-6 1- inch slices French bread
- 1/2 cup shredded Murray's Fondue mix cheese gruyere, raclette and fontina combined
Instructions
- Stir butter, onions, salt and pepper in the crock.
- Cover and cook on low for 8-10 hours until caramelized.
- At this point you can chill the onions for a few days until needed, or continue.
- Place onions in a large saucepan and stir in the flour.
- Add the wine, beef stock, cognac, ground bay and rubbed sage.
- Bring mixture to a boil, stirring, and stir for about one minute until it thickens slightly.
- Place soup in a stoneware crock and top with bread and cheese; broil until cheese melts and browns slightly. Or separately toast the bread with cheese and dunk in soup if you don't have heatproof bowls.
Notes
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What a great idea to prep the onions ahead of time utilizing the crock post! Makes this recipe so much more “hands off”!
We always order French onion soup when we’re out, but rarely make it at home. Love this slow cooker option.