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favorite slow cooker french
Favorite Slow Cooker French Onion Soup
Prep Time
15 mins
Cook Time
12 hrs
Total Time
12 hrs 15 mins


Course: Slow Cooker, Soup
Cuisine: All-American, French
Keyword: beef broth, cheese, onions
Servings: 8 servings
  • 1/4 cup unsalted butter
  • 6 sprigs fresh thyme
  • 2 bay leaves
  • 16 cups vertically sliced large sweet onions
  • 1 tablespoon sugar
  • 6 cups unsalted beef stock, homemade or pre-made
  • 2 tablespoons red wine vinegar
  • 1 1/2 teaspoons kosher salt
  • 1 teaspoon black pepper
  • 24 1/2-inch slices French baguette, buttered and toasted
  • 1 1/4 cups shredded Gruyère or mozzarella cheese
  1. In the bottom of a 5 or 6 quart slow cooker, add butter, thyme sprigs bay leaves, sliced onions and sugar. Turn slow cooker to low and cook for 8-10 hours.

  2. To the onion mixture in slow cooker, add beef stock, red wine vinegar, salt and pepper. Heat on high until hot. Meanwhile place oven rack at least 6 inches under broiler. Preheat broiler. Butter one side of baguette slices. Place slices, buttered side up on baking sheet. Place baking sheet under broiler. Broil slices just until toasted.

  3. To Serve: Ladle hot French onion soup into oven-proof soup bowls. Float one or two slices of toasted baguette slices on top of soup. Sprinkle shredded cheese over the top. Place under the broiler until the cheese is melted and bubbly.

Recipe Notes

Recipe Note: 16 cups equals roughly 5 lbs of onions.