Name: Slow Cooker French Onion Meatballs Recipe
Prep time: 15 min
Cook time: 4 h
Total time: 4 h 15 min
Cuisine: French-American
Ingredients: 1 ½ pounds frozen or homemade meatballs; 2 large yellow onions, thinly sliced; 2 tablespoons unsalted butter; 1 tablespoon olive oil; 2 teaspoons balsamic vinegar; 1 tablespoon Worcestershire sauce; 2 teaspoons garlic, minced; 2 cups beef broth; 1 tablespoon cornstarch mixed with 2 tablespoons water; Salt and black pepper to taste; 1 ½ cups shredded Gruyère or Swiss cheese; Fresh thyme for garnish (optional)

Description

These slow cooker French onion meatballs are rich, savory, and bursting with classic French onion flavor. Simmered in a caramelized onion and beefy broth, they’re perfect served over mashed potatoes, rice, or with crusty bread for an easy, comforting meal or party appetizer.

Ingredients

Scale

Meatballs

1 ½ pounds frozen or homemade meatballs

Onion Sauce

2 large yellow onions, thinly sliced
2 tablespoons unsalted butter
1 tablespoon olive oil
2 teaspoons balsamic vinegar
1 tablespoon Worcestershire sauce
2 teaspoons garlic, minced
2 cups beef broth
1 tablespoon cornstarch mixed with 2 tablespoons water
Salt and black pepper to taste

Toppings

1 ½ cups shredded Gruyère or Swiss cheese
Fresh thyme for garnish (optional)

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Instructions

Caramelize Onions: In a skillet over medium heat, melt the butter and olive oil, then add the sliced onions. Cook for 15–20 minutes, stirring frequently, until onions are golden brown and caramelized.
Add Garlic and Balsamic Vinegar: Stir in the minced garlic and balsamic vinegar, cooking for another 1–2 minutes to enhance the flavor.
Transfer to Slow Cooker: Move the caramelized onions into the slow cooker. Add the meatballs, beef broth, and Worcestershire sauce. Stir gently to combine all ingredients evenly.
Slow Cook: Cover and cook on low for 4–5 hours or on high for 2–3 hours until meatballs are heated through and flavors meld.
Thicken Sauce: About 30 minutes before the end of cooking, stir in the cornstarch slurry to thicken the sauce, allowing it to cook uncovered if possible for better thickening.
Add Cheese and Melt: Sprinkle shredded Gruyère or Swiss cheese on top of the meatballs, cover, and let it melt before serving.
Garnish and Serve: Garnish with fresh thyme if desired and serve over mashed potatoes, egg noodles, or toasted baguette slices for a delightful meal.

Notes

Use homemade meatballs for richer flavor or save time with quality frozen meatballs.
Gruyère is traditional, but Swiss or mozzarella cheese work well as substitutes.
Serve over mashed potatoes, egg noodles, or toasted baguette slices for best results.
Make sure to stir the cornstarch slurry well before adding to prevent clumps.
For a gluten-free option, ensure meatballs and beef broth are gluten-free certified.