Name: Cheesy French Onion Meatball Subs
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Cuisine: American/French Fusion
Ingredients: 1 lb ground beef; 1 egg; 1/2 cup bread crumbs; 2 cloves garlic, minced; Salt and pepper to taste; 2 large yellow or sweet onions, thinly sliced; 2 tbsp butter; 1 cup beef broth; 1 tbsp Worcestershire sauce; 1 tsp thyme; 4 slices provolone cheese (or Gruyère); 4 sub rolls or hoagie buns

There’s something about the cozy richness of French onion soup that I absolutely love—and when that comforting flavor meets the satisfying heartiness of a meatball sub, it turns into something irresistible. These Cheesy French Onion Meatball Subs take juicy meatballs, caramelized onions, and gooey melted cheese and wrap them up in a toasted sub roll. It’s the kind of meal that feels like a warm hug, perfect for chilly evenings or whenever I need a serious comfort food fix.

Why You’ll Love This Recipe

I love how this recipe takes all the elements of French onion soup—deep, sweet onions and savory broth—and gives it a whole new life as a hearty sandwich. The meatballs soak up all that oniony flavor while the cheese turns golden and bubbly under the broiler. It’s easy to make, incredibly satisfying, and way more exciting than a standard sub. Plus, it’s a great twist on a classic for anyone who loves a good mashup dish.

Ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

Ground beef
Egg
Bread crumbs
Garlic, minced
Salt and pepper
Onion (yellow or sweet), thinly sliced
Butter
Beef broth
Worcestershire sauce
Thyme
Provolone cheese (or Gruyère for a more authentic French onion flavor)
Sub rolls or hoagie buns

Directions

I start by making the meatballs. In a bowl, I mix ground beef with egg, bread crumbs, minced garlic, salt, and pepper. Once it’s combined, I form the mixture into medium-sized balls and bake or pan-sear them until browned and cooked through.
While the meatballs cook, I caramelize the onions. I melt butter in a pan over medium heat and slowly cook the sliced onions until they turn soft and golden brown—this takes patience, about 25–30 minutes.
I add the beef broth, Worcestershire sauce, and thyme to the onions and let it simmer until slightly reduced. Then I return the meatballs to the pan to soak in that rich broth for a few minutes.
I split the sub rolls and toast them lightly. Then I fill each one with the meatballs and spoon over the caramelized onions and a bit of the broth.
I lay slices of cheese over the top and pop the subs under the broiler until the cheese melts and starts to bubble and brown.
Once they’re hot and cheesy, I serve them immediately with extra napkins—it’s gloriously messy and totally worth it.

Servings and timing

This recipe makes about 4 subs and takes approximately 50 minutes from start to finish. That includes time to make and cook the meatballs, caramelize the onions, and assemble and broil the sandwiches.

Variations

I sometimes swap ground beef for ground turkey or chicken for a lighter version. For a little kick, I add a few red pepper flakes to the meatball mix. When I want extra richness, I use Gruyère cheese, which melts beautifully and pairs perfectly with the onion flavor. And for a gluten-free option, I use gluten-free breadcrumbs and serve it in lettuce wraps or on gluten-free rolls.

storage/reheating

If I have leftovers, I store the meatballs and onions separately from the bread to keep the rolls from getting soggy. I keep everything in airtight containers in the fridge for up to 3 days. To reheat, I warm the meatballs and onion mixture in a pan or microwave, then assemble and broil the subs fresh when I’m ready to eat.

FAQs

How do I get my onions to caramelize properly?

I cook them low and slow with plenty of butter and a pinch of salt. Stirring occasionally and being patient is the key—they’ll take at least 25–30 minutes to get that deep golden color.

Can I use frozen meatballs?

Yes, I can use store-bought frozen meatballs to save time. I just heat them according to the package, then simmer them in the onion broth before assembling the subs.

What’s the best cheese for these subs?

Provolone melts beautifully and gives a mild, creamy taste. But when I want a sharper flavor, I use Gruyère—it adds that classic French onion soup depth.

Can I make this vegetarian?

Yes, I can substitute the meatballs with plant-based ones and use vegetable broth instead of beef. The onions and cheese still deliver great flavor.

How do I stop the rolls from getting soggy?

I toast the rolls lightly before filling them and make sure not to overload them with broth. I spoon in just enough for flavor without drenching the bread.

Conclusion

Cheesy French Onion Meatball Subs bring together two comfort food favorites into one mouthwatering sandwich. With juicy meatballs, savory-sweet onions, and melty cheese packed into a toasted bun, it’s the kind of meal I crave when I need something hearty and indulgent. Whether I make them for a weekend dinner or game day treat, these subs never fail to impress—and I always wish I made more.