Slow Cooker French Onion Soup

5 from 2 votes

The most incredibly delicious French onion soup ever, the quintessential Winter soup, with its obligatory slice of toasted bread with melted cheese on top…yum!

Prep Time25

Cook Time6

Caramelizing Onions1

Total Time7 25

Course: dinner, lunch, Soup

Cuisine: American

Keyword: Slow Cooker French Onion Soup

Servings:

Calories: 286kcal

Author: Jessica & Nellie

Ingredients

5-6 large yellow onions
4 tablespoons butter
3 tablespoons white flour
½ cup brandy or cognac
6 cups of beef stock
2 bay leaves
4 sprigs of fresh thyme or 1 teaspoon dried)+ some more for the final garnish
Salt and pepper to taste
Baguette bread one or two slices per bowl of soup
1 cup Grated cheese: Swiss or Gruyere Gouda, Parmesano or Mozzarella

Instructions

Step by step instructions for how to make Slow Cooker French Onion Soup

First step is the Caramelization of the onions! Start by slicing the onions thinly, the thinner the better so they cook a bit faster.
In a large pan on medium heat, add the butter and melt.
Then, add the sliced onions and let cook for 1 minute or so before you stir them.
Next, add a little bit of salt to the onions and mix well, turn to low heat and keep stirring every 5 minutes or so.
When you start to see the onions browning, add a splash of the cognac to deglaze and keep cooking until all the onions are translucent and a soft golden brown.
After than, add the flour and cook it for 1-2 minutes or so, stirring constantly to avoid it from burning. Then, add a splash of the beef stock and dilute the flour in it and mix well to combine.
Once the flour has mixed well and completely dissolved, transfer the caramelized onions from the pan to the slow cooker.
Continue to add the rest of the beef stock and herbs to the slow cooker and mix well.
Set on low heat and let cook for 5-6hours.
Towards the last 30 minutes, carefully taste the soup and add the salt and pepper as desired.

Preparing the bread and putting together the final dish

Preheat the oven to 400º F. Slice the baguette bread, place on baking sheet and toast bread for 5-7 minutes.
In oven safe soup bowls power the onion and broth mixture into each bowl, top each bowl with 2 slices of bread and add some grated cheese on top.
Change oven setting to broil.
Place the full soup bowls in the oven and broil for 8-10 minutes. Be very careful when removing from the oven!

Step by step instructions for Stovetop method

First step is the Caramelization of the onions! Start by slicing the onions thinly, the thinner the better so they cook a bit faster. Yes, you are going to cry a lot!
In a Dutch oven on medium heat, add the butter and melt. If you do not have a Dutch oven, a large pot will also do.
Then, add the sliced onions and let cook for 1 minute or so before you stir them.
Next, add a little bit of salt to the onions and mix well, turn to low heat and keep stirring every 5 minutes or so.
When you start to see the onions browning, add a splash of the cognac to deglaze and keep cooking until all the onions are translucent and a soft golden brown.
After than, add the flour and cook it for 1-2 minutes or so, stirring constantly to avoid it from burning.
Then, add a splash of the beef stock and dilute the flour in it and mix well to combine.
Continue to add the rest of the beef stock and herbs to the pot and mix well.
Set on low heat and let cook for 5-6hours. Towards the last 30 minutes, carefully taste the soup and add the salt and pepper as desired.
Once it has simmered for 2-3 hours, remove it from heat.
Follow the same instructions for Preparing the bread and final dish

Notes

This Slow Cooker French Onion Soup is so delicious and perfect to warm you up on cold winter day. We hope you enjoy it as much as we do!

Nutrition