How to Make French Onion Soup in a Slow Cooker: Easy Crockpot Recipe

Transform your mealtime with a delightful twist on a classic favorite: our slow cooker French onion soup recipe. This comforting dish brings together savory flavors in a convenient and time-saving way, ensuring a delicious meal awaits you without the fuss. Utilizing a crockpot, this recipe retains all the richness and aroma of traditional French onion soup, with an effortless preparation method that’ll quickly make it a staple in your home.

I still remember the chilly winter evening when my grandmother first introduced me to this soup. She had a knack for making everyone at the table feel warm and cherished, vividly explained through the steam rising from those onion-laden bowls. Her secret? A reliable old slow cooker that perfumed the entire house with the enchanting aroma of simmering onions, herbs, and broth, drawing my family to the kitchen with eager anticipation.

Why You’ll Love This Recipe

This recipe is a game-changer for busy days when you crave comfort without spending hours in the kitchen. With minimal prep and the slow cooker doing the heavy lifting, you’ll enjoy a meal that’s rich in flavor and nutrition. The method locks in flavors effectively, ensuring that each spoonful is a harmonious blend of sweetness from the caramelized onions and the depth from the broth. It’s ideal for home cooks seeking a no-fuss way to enjoy gourmet-style cuisine at home.

Ingredients Notes

To ensure the best results, use sweet onions for their natural ability to caramelize beautifully, creating a deeper flavor. Beef broth is the traditional choice for a robust taste, but a high-quality vegetable broth can vegetarianize this dish easily. Incorporate fresh thyme and a splash of white wine for a more complex flavor profile. If you’re unable to find Gruyère cheese, Swiss or even mozzarella are viable alternatives that also deliver that wonderful, melty topping.

Recipe Steps

Step 1

Start by thinly slicing 6-8 large sweet onions. This is crucial as thin slices will caramelize more evenly and cook down better in the crockpot.

Step 2

Place the sliced onions into your slow cooker, along with butter, allowing them to cook on high for about an hour, stirring occasionally, until they start to caramelize.

Step 3

Add in garlic, a sprig of thyme, and a bay leaf. Then pour in 7 cups of beef broth and a few tablespoons of white wine. Stir well to combine.

Step 4

Cover and cook on low for 6 to 8 hours, allowing the flavors to meld together beautifully. This step ensures a rich, flavorful broth.

Step 5

To finish, toast slices of baguette, top each with Gruyère cheese, and broil till the cheese bubbles. Place on top of the soup for serving.

Storage Options

To store leftovers, let the soup cool to room temperature before transferring it to airtight containers. It can be refrigerated for up to a week. For longer storage, consider freezing in portion-sized containers, which can be thawed overnight in the fridge before use. Reheat on the stove or in the microwave, ensuring thorough heating for the best flavor retention.

Variations & Substitutions

For a vegan version, switch out the butter for a plant-based alternative and use vegetable broth instead of beef. You can also experiment by adding mushrooms for a deeper umami flavor or a pinch of nutmeg for a holiday twist. For those who prefer a gluten-free option, omit the bread or use a suitable substitute and check that your broth is gluten-free.

Frequently Asked Questions

Can I make this soup without wine?

Absolutely! While the wine adds a touch of acidity and depth, it’s entirely optional. You can substitute with an equal amount of additional broth or a tablespoon of balsamic vinegar for a similar effect.

What’s the best cheese to use for the topping?

Gruyère cheese is traditional due to its melting properties and flavor profile. However, Swiss cheese, Provolone, or even a sharp cheddar can work if those are more accessible for you. Each provides a unique twist on the classic recipe.

Is there a way to speed up the cooking process?

If you’re short on time, you can caramelize the onions on the stovetop before adding them to the slow cooker. This step reduces the crockpot cooking time significantly by almost an hour while maintaining the same rich flavor.

How to Make French Onion Soup in a Slow Cooker: Easy Crockpot Recipe

This easy Crockpot French Onion Soup recipe results in a rich, flavorful soup perfect for a cozy night in. Serve it with crusty bread and melted cheese for a classic finish.

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Prep Time: 15 minutes minutes

Cook Time: 8 hours hours

Total Time: 8 hours hours 15 minutes minutes

Servings: 6

Calories: 120kcal

Ingredients

 

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Main Ingredients

• ▢ 3 pounds yellow onions thinly sliced
• ▢ 1 tablespoon olive oil or butter
• ▢ 2 teaspoons sugar to aid in caramelizing
• ▢ 8 cups beef broth low sodium
• ▢ 1 cup dry white wine optional
• ▢ 2 tablespoons balsamic vinegar
• ▢ 1 teaspoon thyme dried
• ▢ 0.5 teaspoon black pepper freshly ground
• ▢ 1 loaf French bread sliced, toasted
• ▢ 2 cups Gruyere cheese grated

Instructions

Preparation Steps

• Heat olive oil in a large skillet over medium heat. Add sliced onions and sugar. Cook, stirring often, for about 15 minutes until onions are soft and caramelized.
• Transfer caramelized onions to the slow cooker. Add beef broth, wine, balsamic vinegar, thyme, and black pepper. Stir to combine.
• Cover and cook on low for 8 hours until flavors meld together beautifully.
• Preheat broiler. Ladle soup into oven-safe bowls. Top each with a slice of French bread and grated Gruyère cheese.
• Place bowls under the broiler until the cheese is bubbly and golden. Serve hot.

Notes

For a vegetarian option, replace beef broth with vegetable broth.