Go Back

Slow Cooker French Onion Meatballs

Frozen homestyle meatballs slow cooked with thinly sliced onions in a rich French onion and beef broth gravy, thickened and finished with melted Gruyère cheese for a deeply savory comfort dinner.
Print Recipe Pin Recipe
Prep Time 10 minutes
Cook Time 5 hours
Total Time 5 hours 10 minutes
Servings: 6 servings
Course: Dinner, Main Course
Cuisine: American, French-American
Calories: 490
Ingredients Equipment Method Notes

Ingredients
  

  • 29 oz frozen homestyle or beef meatballs 26 to 32 oz bag; do not use Italian-style meatballs
  • 2 medium yellow onions thinly sliced into half-moons; as thin as possible
  • 2 cloves garlic minced
  • 2 cup low-sodium beef broth low-sodium recommended; the other sauce components are already salty
  • 1 can condensed French onion soup 10.5 oz
  • 1 package brown gravy mix or onion soup mix 1 oz packet
  • 1 tbsp white wine vinegar or balsamic vinegar
  • 1 tsp dried thyme
  • 1 tsp black pepper
  • 2 tbsp cornstarch mixed with 1/4 cup cold water for slurry
  • 0.25 cup cold water for cornstarch slurry
  • 1.5 cup shredded Gruyère cheese Swiss or Provolone can substitute
  • fresh parsley or thyme for garnish

Equipment

  • 6-quart Slow Cooker
  • medium mixing bowl
  • whisk
  • Small bowl for cornstarch slurry

Method
 

  1. Spread the thinly sliced onions in an even layer across the bottom of a 6-quart slow cooker.
  2. Pour the frozen meatballs directly over the onion layer in a relatively even layer.
  3. Whisk together the beef broth, condensed French onion soup, brown gravy mix, minced garlic, vinegar, dried thyme, and black pepper in a medium bowl until the gravy mix has fully dissolved. Pour over the meatballs and onions. Stir gently to distribute.
  4. Cover and cook on Low for 5 to 6 hours or on High for 2.5 to 3.5 hours. Stir halfway through if possible.
  5. About 20 minutes before serving, whisk the cornstarch and cold water until completely smooth. Stir the slurry into the slow cooker. Switch to High if on Low. Cook uncovered for 10 minutes, stirring once, until the gravy is glossy and thickened.
  6. Sprinkle the shredded Gruyère evenly over the surface. Replace the lid and cook for 10 to 15 minutes until the cheese is fully melted and bubbly. Optional: transfer the oven-safe insert under the broiler for 2 to 3 minutes for a golden cheese crust.
  7. Garnish with fresh parsley or thyme and serve hot over mashed potatoes, egg noodles, or in toasted hoagie rolls.

Notes

Storage: Store in an airtight container for up to 5 days. Add a splash of beef broth when reheating to loosen the thickened gravy. Freeze for up to 3 months; thaw overnight before reheating. Substitutions: Swiss, Provolone, or white cheddar replace Gruyère. Add a tablespoon of dry sherry or Worcestershire to the sauce for deeper flavor. Homemade raw meatballs can replace frozen; cook on Low for 4 to 5 hours to reach 165°F internal temperature. Pro tips: Always use homestyle or plain meatballs, not Italian-style. Slice onions as thin as possible for best results. Switch to High for the thickening stage. Use the broiler finish for the best cheese crust if the insert is oven-safe.