Warm, cozy, and full of flavor—these Crockpot French Onion Meatballs are pure comfort food. Think tender meatballs simmered low and slow in rich, caramelized onion gravy with a layer of melty cheese on top. It’s a dish that feels fancy but takes almost no effort. I make these when I want something hearty without turning on the oven or making a mess. And the best part? They taste even better the next day.
Why I Love This Recipe
This recipe is like a warm hug in a bowl. It’s got all the rich flavors of French onion soup, but way easier to make. I came up with it one winter when I had leftover meatballs and no energy to cook. I tossed everything into the slow cooker and magic happened.
- It’s made in one pot—easy cleanup
- Perfect for meal prep or lazy nights
- You can serve it with pasta, mashed potatoes, or crusty bread
- It makes your kitchen smell amazing
- Leftovers are even better
Servings and Cook Time
Serves: 6
Cook Time: 4–5 hours on LOW or 2–3 hours on HIGH
What You’ll Need
- 1 (26 oz) bag frozen homestyle meatballs
- 2 large yellow onions, thinly sliced
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 1 tablespoon Worcestershire sauce
- 1 tablespoon balsamic vinegar
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- 1 teaspoon kosher salt
- ½ teaspoon black pepper
- 1 tablespoon cornstarch
- 1 ½ cups beef broth
- 1 ½ cups shredded mozzarella cheese
- 1 cup shredded Gruyère cheese
- Fresh thyme (for garnish, optional)
Pro Tips
- Slice the onions thin for even caramelization
- Use frozen meatballs to save time, but make sure they’re homestyle—not Italian
- Mix the cornstarch into cold broth to prevent clumps
- Add the cheese right before serving so it stays gooey
- Use a slow cooker liner for easy cleanup
Tools You’ll Need
- Crockpot or slow cooker
- Sharp knife
- Cutting board
- Measuring cups and spoons
- Cheese grater (if using block cheese)
- Mixing bowl
- Small whisk or fork
Substitutions and Variations
- Swap Gruyère for Swiss or provolone
- Use homemade meatballs if you’ve got extra time
- Add sliced mushrooms with the onions for extra depth
- Make it spicy with a pinch of red pepper flakes
- Use vegetable broth for a lighter version
Make Ahead Tips
- Slice onions and shred cheese a day ahead
- Mix broth, spices, and cornstarch in a jar and refrigerate overnight
- Assemble everything in the crock the night before and refrigerate, then start cooking in the morning
How To Make Crockpot French Onion Meatballs
Step 1: Caramelize the Onions
Melt 2 tablespoons unsalted butter and 1 tablespoon olive oil in a skillet over medium heat. Add 2 large yellow onions, thinly sliced. Cook for 15-20 minutes, stirring often, until deeply golden and caramelized.
Step 2: Add Onions and Meatballs to Crockpot
Transfer caramelized onions to the crockpot. Add the full 26 oz bag of frozen homestyle meatballs right on top.
Step 3: Make the Broth Mixture
In a bowl, whisk together 1 tablespoon Worcestershire sauce, 1 tablespoon balsamic vinegar, 1 teaspoon garlic powder, 1 teaspoon onion powder, 1 teaspoon kosher salt, ½ teaspoon black pepper, and 1 tablespoon cornstarch. Slowly whisk in 1 ½ cups beef broth until smooth.
Step 4: Pour Broth Over Meatballs and Cook
Pour the broth mixture evenly over the meatballs and onions in the crockpot. Cover and cook on LOW for 4–5 hours or HIGH for 2–3 hours.
Step 5: Add Cheese and Melt
Once cooked, sprinkle 1 ½ cups shredded mozzarella and 1 cup shredded Gruyère evenly over the top of the hot meatballs. Cover the lid and let sit for 10–15 minutes until melted and bubbly.
Step 6: Serve and Garnish
Spoon the cheesy French onion meatballs into a serving bowl. Sprinkle with fresh thyme and serve hot.
Macros (per serving – approx.)
- Calories: 410
- Protein: 22g
- Carbs: 16g
- Fat: 28g
- Fiber: 1g
- Sugar: 4g
Why This Recipe Works (Quick Science)
The onions caramelize slowly to bring out their natural sweetness, which pairs perfectly with the savory meatballs. The cornstarch thickens the broth into a silky gravy. And melting cheese on top adds creaminess and pulls everything together like a warm French onion soup.
Common Mistakes
- Skipping the onion caramelizing step – You won’t get the depth of flavor
- Using too much cheese – It can overpower the dish
- Adding cornstarch directly to the crockpot – It will clump instead of thickening
- Not covering meatballs with broth – They’ll dry out
What to Serve With
- Toasted baguette slices (perfect for scooping)
- Creamy mashed potatoes
- Buttered egg noodles
- Roasted green beans or asparagus
- A crisp green salad with vinaigrette
FAQ
Can I use turkey meatballs?
Yes! Just make sure they’re plain or homestyle flavor.
Can I freeze leftovers?
Yep. Let cool completely, then freeze in a sealed container for up to 2 months.
Can I cook this on the stovetop?
Yes, just simmer everything in a covered pot for 30–40 minutes, then add the cheese at the end.
Can I double the recipe?
Totally. Just make sure your crockpot is big enough.
Do I have to caramelize the onions first?
It’s not required but it makes a HUGE difference in flavor.
Leftovers and Storage
Store leftovers in an airtight container in the fridge for up to 4 days. Reheat in the microwave or on the stove. Add a splash of broth if the sauce thickens too much. You can also freeze it for up to 2 months—just thaw overnight before reheating.
Wrap-Up
I hope you give this recipe a try next time you’re craving something hearty and low-effort. These Crockpot French Onion Meatballs are rich, comforting, and just a little bit fancy. If you try it, drop a comment and let me know how it turned out—or ask any questions!