There’s nothing cozier than a bowl of French onion soup. The rich beef broth, sweet golden onions, and gooey cheese toast on top make it special. The best part about this Slow Cooker French Onion Soup? You don’t even have to stand at the stove caramelizing onions for hours. The slow cooker does it for you! With just 20 minutes of prep, the onions gently cook low and slow until they’re soft, golden, and naturally sweet. Comfort food made easy, right in your own kitchen.
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🗝️ Recipe's key points
- The slow cooker offers a hands-off approach to making this comforting and rich-flavored cheesy French onion soup.
- Just spend 20 minutes preparing in the morning. Then, you can enjoy dinner while you focus on your day!
- The long, gentle cooking process enhances the flavors of the caramelized onions and rich beef stock. This creates a soup with amazing depth of flavor.
Get ready to come home to a kitchen filled with a delicious smell. You will find a restaurant-quality meal that is easy to serve!
🛒 Ingredients
This is an overview of the crockpot French Onion Soup ingredients. You'll find the full measurements and instructions in the recipe card (printable) at the bottom of the page.
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- Onions – Use Vidalia onions for a sweeter Crockpot French onion soup, or yellow onions, if you prefer.
- Unsalted butter – Melted for easy mixing with the onions.
- Black Pepper & Kosher Salt – Taste to adjust at the end of the cooking.
- Beef stock – Use low-sodium beef stock for better control of the salt level in your soup. You could use beef broth instead, but it won't create as rich a flavor or as thick a consistency that stock will.
- Marsala wine – I used Marsala wine to add sweetness to this easy French onion soup recipe. You can also use dry white wines like Sauvignon Blanc or Pinot Gris.
- Fresh thyme – For a pop of earthy notes.
- Whole-wheat baguette – Used to make the crispy cheese toasts that top the bowls of soup.
- Gruyère cheese – Shredded for easy sprinkling and melting. Parmesan cheese, Swiss cheese, provolone cheese, or mozzarella will also work in this soup.
🗒 Instructions
This is an overview of the best French Onion Soup recipe instructions. Full instructions are in the recipe card at the bottom of the page.
- Coat a 4-quart slow cooker with cooking spray.
- Mix the onions, butter, and pepper in the slow cooker. Cover it and cook on LOW until the onions are very soft and deep golden brown, about 10 hours.
- Stir in the stock, marsala, thyme and salt.
- Cover and cook on HIGH until the flavors are blended, about 2 hours.
- Preheat the broiler with the oven rack 6 inches from the heat.
- Place the baguette slices on a baking sheet, and sprinkle evenly with the Gruyère.
- Broil until the Gruyère melts, 2 to 3 minutes.
- Ladle the soup into serving bowls and add the cheesy bread topping. Garnish each bowl with the additional thyme, if desired.
🥫 Storage
Store leftover slow cooker French onion soup in an airtight container in the fridge for up to 5 days without the cheese toasts. Reheat on the stovetop or in the microwave and add freshly toasted cheese baguette slices.
This soup also freezes well for up to 3 months, without the cheese toasts. Thaw overnight in the fridge and prepare fresh cheese toast toppings while you reheat the soup.
📚 Variations
- Type of wine: Classic French onion soup with beef broth is great with white or red wine, depending on your preferences. For white wines, use Sauvignon Blanc or Pinot Gris. For red wines, I recommend Pinot Noir or Merlot.
- Other boozy options: For even more rich flavor, consider adding a splash of dry sherry or cognac. Only add these after the soup is done cooking.
- No-alcohol version: Feel free to skip the alcohol if you prefer. Instead, add a splash of balsamic vinegar at the end to enhance the flavor.
- Herbaceous twist: Fresh thyme is the ideal herb for this easy French onion soup recipe. You can also add a bay leaf to the soup for more flavor. Just remember to take it out before serving!
- To thicken soup: For a thicker soup, mix in flour after the first session of cooking.
- Stock versus broth: Use beef broth instead of stock, if needed. This may result in a thinner consistency.
- Gluten-free: Gluten-free bread slices can be used to make this soup suitable for food allergies.
👩🏻🍳 Tips
- Day-old bread is perfect for making the cheese bread topping. If you have enough on hand, don't bother about buying a fresh loaf specifically for making this soup.
- You can adjust the volume of soup made to suit the size of the slow cooker that you have. I've used a 4-quart slow cooker for this recipe, but you can make a larger serving in a 6-quart slow cooker.
- Be sure to spray the slow cooker pot with cooking spray at the start. This will help prevent food from sticking and burning.
🤔 FAQs
Beef stock is made by simmering bones, often with some meat, for an extended period. This process gives it a richer flavor and more body. Beef broth is primarily made with meat and seasonings, making it lighter yet still flavorful. Either works for this soup!
Yes! Beef broth gives the soup its rich flavor. However, chicken or vegetable broth will also taste great if that’s what you have.
Gruyère is the classic choice for its nutty flavor and perfect melt, but Swiss or even provolone can work beautifully.
Nope! That’s the beauty of this recipe — the slow cooker does the work for you. After about 10 hours on low, the onions get soft, golden, and sweet. This gives the soup a classic caramelized flavor without needing much stirring on the stovetop.
Absolutely. Just freeze the soup without the bread and cheese topping. When ready to serve, thaw, reheat, and add fresh cheesy toast.
📗 Related Recipes
There's nothing quite as comforting as crockpot soups for winter! Here are some my top picks that'll keep you toasty from the inside out:
- Buffalo Chicken Soup: Turn the classic, spicy kick of Buffalo wings into a warm, hearty chowder perfect for a cold day.
- Creamy White Lasagna Soup: Enjoy all the comforting flavors of white lasagna in a simpler, creamy soup form.
- Cheddar Potato Broccoli Soup: A quintessential comfort food, this ultra-creamy and cheesy soup is both hearty and satisfying.
🍽 What to serve with Easy Slow Cooker French Onion Soup
This slow cooker French onion soup is the perfect starter for any steak, pork, or chicken dinner. Otherwise, if you want to enjoy your soup as the star of the show, consider pairing it with Arugula Salad or a side of vegetables.
🔪 All Our Way recommends the following
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You’ll need the following items to make this crockpot French Onion Soup recipe successfully.
- Cooking spray - Coats the pot to prevent sticking and burning.
- Slow Cooker or Crockpot - I've used a 4-quart slow cooker, but you could use a 6-quart slow cooker instead.
- Chef's knife - Ideal for preparing ingredients, such as sliced onions.
- Cutting board - To prepare the ingredients.
- Liquid measuring cup - To accurately measure cooking liquids, such as stock and wine.
- Cheese grater - Essential for preparing your freshly shredded cheese for the sliced baguettes.
📞 Chiacchierata (chat)
So, amici, are you ready to cozy up with a bowl of this Slow Cooker French onion Soup? It's proof that comfort food doesn't have to mean complicated cooking. Just a little prep, a slow simmer, and ECCO — you've got caramelized cipolle (onions), a rich beef brodo (broth), and gooey cheese pane tostato (toast) waiting to warm you up. Perfect for chilly nights, lazy Sundays, or when you just want to spoil yourself a little.
Make this crockpot French Onion Souup once, and I promise it'll become a regular in your dinner rotation. And remember recipes like this are meant to be shared — around the table with family or right here online with friends. So grab your cucchiaio (spoon), dive in, and buon appetito! ,
Tutti a tavolo, è pronto!
If you love this recipe please give it 5 stars ⭐️⭐️⭐️⭐️⭐️.
What's new? Check out my All Our Way Store on Amazon. We'll be adding more items we love and use or wish we had to make cooking fun and easy.
📖 Recipe
Slow-Cooker French Onion Soup with Gruyère Toasts
Equipment Needed
Ingredients
- 10 cups vertically sliced onions from 5 onions
- 2 tablespoons unsalted butter melted
- ½ teaspoon black pepper
- 6 cups unsalted beef stock
- ¼ cup dry Marsala wine
- 1 teaspoon chopped fresh thyme plus more for garnish
- ¾ teaspoon kosher salt
- 12 ounces whole-wheat baguette see Tip, cut into 16 slices
- 5 ounces Gruyère cheese shredded (about 1 ¼ cups)
Instructions
- Coat a 4-quart slow cooker with cooking spray.
- Mix the onions, butter, and pepper in the slow cooker. Cover it and cook on LOW. Cook until the onions are very soft and deep golden brown, which takes about 10 hours.
- Stir in the stock, marsala, thyme and salt. Cover and cook on HIGH until the flavors are blended, about 2 hours.
- Preheat the broiler with the oven rack 6 inches from the heat.
- Place the baguette slices on a baking sheet, and sprinkle evenly with the Gruyère. Broil until the Gruyère melts, 2 to 3 minutes.
- Ladle the soup into bowls. Top with the cheese toasts. Garnish with the additional thyme, if desired.
Notes
👩🏻🍳 Tips
- Day-old bread is perfect for making the cheese bread topping. If you have enough on hand, don't bother about buying a fresh loaf specifically for making this soup.
- You can adjust the volume of soup made to suit the size of the slow cooker that you have. I've used a 4-quart slow cooker for this recipe, but you can make a larger serving in a 6-quart slow cooker.
- Be sure to spray the slow cooker pot with cooking spray at the start. This will help prevent food from sticking and burning.
Nutrition
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