French Onion Soup cooked slowly in a crockpot is the epitome of comfort food—a rich and hearty broth, caramelized onions, and a cheesy, golden-brown crust on top. This recipe transforms humble ingredients into a sumptuous dish that warms you from the inside out. With minimal effort, your kitchen will be filled with the irresistible aroma of onions and garlic as they slowly cook to perfection.

Served with crusty bread and melted Gruyere cheese, each spoonful is a delightful blend of savory flavors. Whether enjoyed on a chilly evening or as a comforting meal any time of the year, this slow cooker French Onion Soup promises to be a family favorite.

French Onion Soup..Slow Cooker

Ingredients:

3 pounds onions, which is around 6 large onions …I weigh

1/2 cup (4 oz) butter, melted

2 cloves garlic, minced

1/2 cup dry sherry wine …I didn’t have any the first time I made this…I do now

8 cups beef stock/broth

1 bay leaf

1/4 tsp dry thyme (or 3 sprigs fresh)…I don’t especially like thyme, so I omitted
salt and pepper to taste …my broth is salted, so I add no salt

Baguette, sliced …I did use baguette …but might the next time, use French bread. (I find a baguette too holey)

8 oz of Gruyere cheese, shredded, divided (check recipes if you wish to use Gruyere and combine with another cheese or two …I used just Gruyere

Instructions:

Step 1:

Cut onions in half, and slice thinly.

Place them in the slow cooker.

Add your melted butter and stir well so all onions are coated.

Put this on low overnight, 10 – 12 hours.

Step 2:

Add the garlic.

Stir sherry into onion mixture; scrape the bottom to dissolve the small bits of browned food.

Step 3:

Throw in the thyme, bay leaf, salt/pepper and broth.

Stir well.

Cook on low for 8 – 10 hours or on High for 4 – 6 hours.

I did a combo of that …when I needed it to be ready, I went with it. After all the onions are cooked …the rest is just melding.

Step 4:

Preheat oven to 400ºF.

Slice bread to 1/2″ thick slices.

Brush both sides lightly with olive oil.

Arrange on a baking sheet and bake 6 – 8 minutes until golden brown at the edges.

I did about 8 minutes …flipped the bread and did another 2 minutes.

Step 5:

Once soup is out, set oven to ‘broil’.

Step 6:

Pour soup into bowls..3/4 full or so.

Sprinkle the top with a bit of your cheese.

Lay the bread on top …and sprinkle the rest of the cheese on top.

Broil for 2-3 minutes …until cheese topping is lightly browned and bubbling.

NOTE: This made 6 bowls for me.

Notes:

Slow Cooking Simplicity: This French Onion Soup recipe takes advantage of the slow cooker’s convenience, allowing you to set it and forget it while the flavors meld and develop.

Richness of Onions: The foundation of this soup is caramelized onions, cooked slowly until they’re sweet and tender, creating a deeply flavorful base.

Customizable Ingredients: While the recipe includes specific ingredients like sherry wine, thyme, and Gruyere cheese, it’s adaptable to personal preferences. For example, omitting or substituting ingredients like thyme or using different cheeses can tailor the soup to your taste.

Overnight Cooking: Overnight cooking in the slow cooker allows for maximum flavor development, making it an ideal option for busy days or when you want a comforting meal ready to enjoy.

Finishing Touch: The broiled cheese topping adds a golden, bubbly finish to each serving, enhancing both the flavor and presentation of the soup.

Yield: This recipe yields approximately six generous servings, making it perfect for family dinners or meal prep for the week.

Serving Suggestions: Serve the soup piping hot with toasted bread slices topped with melted cheese for a complete French Onion Soup experience.

Make-Ahead Potential: French Onion Soup tends to taste even better the next day, so consider making it ahead of time for even more developed flavors.

Adaptability: Feel free to experiment with different bread types, cheeses, or additional garnishes to customize the soup to your liking.

Family Favorite: With its rich flavors and comforting warmth, this slow cooker French Onion Soup is sure to become a beloved family favorite for cozy evenings at home.

Nutrition Information:

Calories: 350 kcal | Total Fat: 20g | Saturated Fat: 10g | Cholesterol: 40mg | Sodium: 900mg | Total Carbohydrates: 30g | Dietary Fiber: 3 | Sugars: 8g | Protein: 10g

Frequently Asked Questions:

Can I use a different type of cheese instead of Gruyere for this French Onion Soup recipe?

Yes, you can use a different type of cheese if you prefer.

Gruyere is traditionally used in French Onion Soup for its nutty flavor and melting properties, but you can experiment with other cheeses like Swiss, Emmental, or even mozzarella.

Can I omit the dry thyme from the recipe if I don’t like it?

Absolutely! The dry thyme adds a subtle herbaceous flavor to the soup, but if you don’t enjoy it, feel free to omit it.

You can still enjoy a delicious French Onion Soup without it.

Can I make this soup without using a slow cooker?

Yes, you can adapt this recipe for stovetop cooking.

Simply sauté the onions and garlic in a large pot until caramelized, then add the remaining ingredients and simmer for about an hour.

The flavors will still meld beautifully.

Can I substitute dry sherry wine with another type of alcohol or omit it altogether?

While dry sherry wine adds depth of flavor to the soup, you can substitute it with a dry white wine or omit it altogether if you prefer.

The soup will still be delicious without it, but the sherry does add a unique touch.

How do I prevent the bread from becoming soggy when serving the soup?

To prevent the bread from becoming soggy, it’s best to toast it lightly before adding it to the soup.

This step helps the bread hold its texture and absorb less liquid from the soup.

Additionally, placing the bread on top of the soup just before serving helps maintain its crispness until it’s enjoyed.

Can I prepare the onions and store them overnight before cooking the soup?

Yes, you can prepare the onions ahead of time and store them in an airtight container in the refrigerator overnight.

This can save you time when you’re ready to cook the soup the next day.

Can I freeze leftover French Onion Soup?

Yes, French Onion Soup freezes well.

Allow the soup to cool completely before transferring it to freezer-safe containers.

Leave some space at the top of the container to allow for expansion during freezing.

Thaw overnight in the refrigerator before reheating.

How long does French Onion Soup last in the refrigerator?

When stored in an airtight container, French Onion Soup can last in the refrigerator for up to 3-4 days.

Reheat it on the stovetop or in the microwave until warmed through before serving.

Can I use vegetable broth instead of beef broth for a vegetarian version of this soup?

Yes, you can substitute vegetable broth for beef broth to make a vegetarian version of this French Onion Soup.

The flavor profile will be slightly different, but it will still be delicious.

Can I use pre-made croutons instead of toasted bread for the topping?

While toasted bread is traditional for French Onion Soup, you can certainly use pre-made croutons if you prefer.

Just be sure they are sturdy enough to hold up in the soup and provide a satisfying crunch.