Slow Cooker French Onion Meatballs (Frozen Meatballs)

Slow Cooker French Onion Meatballs are tender, juicy meatballs simmered in a rich, savory French onion sauce. Slow-cooked to perfection, this family favorite easy dinner recipe makes a cozy dinner for busy nights, and they’re so easy to prep with frozen meatballs, condensed French onion soup, and fresh onions. 

If you want more French onion recipes be sure and make Oven Baked French Onion Soup Rice and French Onion Chicken Casserole.

Crockpot French Onion Meatballs With Frozen Meatballs

If you want a cozy hearty meal for dinner – this easy slow cooker recipe for French Onion Meatballs is just what you need!

Only minutes of prep time needed and the hardest part is slicing up some fresh onion. Minimal effort needed which means you can have more time to do all the other stuff rather than spend hours cooking and prepping. 

The base of the recipe are frozen meatballs which is always my go-to ‘dinnertime’ secret because I think they taste just as good as homemade and they hold together better in the slow cooker over the longer cook time. Pair it with some convenient canned items like condensed French onion soup, fresh garlic, and beef broth; and you have a flavorful gravy sauce that is created during the slow cook time. 

Perfect for busy weeknights, cold weekends when you want dinner ready to go, or they’re even a yummy appetizer (serve alongside some toothpicks) for game day gatherings. 

How To Make Slow Cooker French Onion Meatballs (Printable Recipe Card)

Light spray the inside of your slow cooker with nonstick cooking spray. Dump the frozen meatballs into the slow cooker. 

Layer the thinly sliced onions over top the meatballs.

Cut the butter into small pieces and scatter them across the onions. 

In a medium bowl, whisk together the condensed French onion soup, beef broth, garlic, and black pepper. Pour the mixture over the meatballs and onions.

Cover and cook on LOW heat for 4-5 hours.

Sprinkle the shredded gruyere cheese evenly over the top. Cover again, and let it cook for an additional 10 minutes or until the cheese has fully melted and is gooey. 

Serve the meatballs hot, directly from the slow cooker, with a side of Texas toast for dipping, over egg noodles or pasta, over cooked white rice, or eat the meatballs as is. 

How To Store Leftovers and Reheating Instructions

• Refrigerator : Store leftover meatballs and sauce in an airtight container for up to 3 days. Reheat the meatballs and sauce in a skillet pan over medium heat, or reheat individual portions in the microwave until heated through. 
• Freezer : Transfer the cooled meatballs and sauce to a freezer-safe container or bag and freeze for up to 2 months. Thaw overnight in the fridge before reheating. 
• Make-Ahead Freezer Meal (Uncooked) : Add all the ingredients (NOT the gruyere cheese or chopped parsley for garnish) into a gallon-size freezer-safe Ziploc bag. Let the excess air out and zip it closed. Freeze for up to 3 months. Let it thaw overnight in the fridge before cooking in the slow cooker. Or you can add it to the slow cooker, from frozen, and add some additional cook time. Add the gruyere cheese as directed in the recipe. 

Substitutions and Ingredient Notes

• Frozen Meatballs : A quick and easy shortcut that still tastes homemade. My favorite frozen meatball is actually the Great Value brand (surprisingly!). For best results use the beef homestyle meatballs or turkey meatballs. I don’t recommend using Italian meatballs as the extra seasonings won’t pair well with the French onion flavors we have going on in this recipe. 
• Yellow Onions : Sweet onions are another option. Make sure they are very thinly sliced in half moon shapes before adding them to the slow cooker. You don’t want huge, thick chunks but rather thin small pieces that soften in the slow cooker and blend with the other ingredients. 
• Butter : Salted butter or unsalted butter can both be used. It just depends on the sodium content you prefer or your dietary restrictions or needs. 
• Beef Broth : Beef stock, beef bone broth, or water + beef bouillon are all great options. Use full salt or low-sodium depending on your preference. I normally use full salted beef bone broth (the Kettle Fire brand) but have also used beef broth and beef stock with just as great results. 
• Gruyere Cheese : This is the best cheese to use for that signature French onion soup flavor. It melts perfectly smooth over top the meatballs and gives it that classic French onion finish. Another option is to use smokey gruyere cheese if you want a smoky note in the meatballs. You could also use freshly shredded white cheddar cheese or mozzarella cheese as a last resort. You will normally find the specialty cheese up in the deli area by the meat counter. 

Can I Use Caramelized Onions?

Use caramelized onion in this slow cooker recipe for even more of that classic French onion flavor. It does take some extra prep work and dishes, but caramelized onions add tons of flavor so it’s never a bad idea! Here is how you can caramelize onions. 

• Simply heat 1 tablespoon of butter in a large skillet pan over medium heat. Add the sliced onions and cook for 20-25 minutes, stirring occasionally, until they’re golden brown and softened. 

How Can I Make The Sauce Thicker? More Like A Gravy?

If at the end of the cook time you feel the sauce is too thin – simply remove 1 cup of the liquid from the slow cooker and place it into a small mixing bowl along with 1 tablespoon cornstarch – whisk it together until it’s smooth and combined well. Pour the liquid back into the slow cooker, stir well, and let it cook for about 10 minutes or until thickened. 

I would recommend thickening the sauce into a gravy BEFORE you add the cheese on top. Once you add the cheese, you don’t really want to disturb the meatballs too much, because classic French onion has that thick melty layer of cheese on top. 

More Slow Cooker Frozen Meatball Recipes

• Crockpot Cranberry Meatballs
• Crockpot Mississippi Meatballs
• Crockpot Jelly Meatballs
• Easy Swedish Meatballs
• Slow Cooker Salisbury Steak Meatballs (Frozen Meatballs)
• Slow Cooker Cheesy Enchilada Meatballs
• Slow Cooker Asian Sesame Meatballs
• Slow Cooker Spaghetti and Meatballs
• EASY Crockpot Meatball Marinara
• Crockpot Sweet and Sour Meatballs (EASY Slow Cooker Recipe)