French Onion Stuffed Meatballs

We’ve turned it into a noodle casserole, we’ve turned it into a chicken skillet… Clearly we love French Onion Soup. Now, it’s taking its turn as meatballs. Stuffed meatballs, that is. Yup. The center of these little guys holds a pocket of sweet caramelized onions and ooey-gooey Gruyere cheese, and they’re every bit as good as they sound.

You start by caramelizing the onions, which takes patience and a little bit of time, but is always well worth it. Then, you make a basic meatball mixture and form it into a little patty in your hand. Place some of the onion mixture and a little cube of cheese in the center and form the patty into a ball around the filling. See? Easy enough.

For the onions and meatballs:
2 tablespoons olive oil, divided
1 large sweet onion, halved and thinly sliced
1 teaspoon dried thyme, divided
1/4 cup beef broth
1/4 cup red wine
1 1/2 lbs ground beef
1/4 cup breadcrumbs
1 large egg, beaten
8 oz Gruyere or Swiss cheese, 2 oz cut into 1/2-inch cubes, the rest grated
For the sauce:
1 3/4 cup beef broth
1/4 cup red wine
2 tablespoons cornstarch
Kosher salt and freshly ground black pepper, to taste

In a large skillet over medium heat, heat 1 tablespoon of the olive oil. Add onions, season with salt and pepper, and cook until caramelized, stirring frequently, about 15-20 minutes.
Add half of the thyme, cook for one minute, and then add 1/4 cup wine and 1/4 cup beef broth.
Cook until liquid has reduced; very little liquid should remain. Remove to a plate or bowl and set aside.
To a large bowl, add ground beef, remaining thyme, breadcrumbs, egg, and about 1 teaspoon of salt and 1/2 teaspoon black pepper. Mix together thoroughly with your hands and divide into 16 equal pieces.
Take a piece of the meat mixture and flatten into a patty. Add a 1/2 tablespoon of the onions and a cube of cheese to the center of the patty and wrap the meat around the onions and cheese to form a meatball. Repeat with remaining meat.
Preheat oven to 375°F.
Heat remaining oil in an oven-safe skillet over medium-high heat. Add meatballs and brown on all sides, turning gently.
Whisk together 1 3/4 cup beef broth, 1/4 cup wine, and cornstarch and pour over browned meatballs.
Place in oven and bake for 15 minutes. Sprinkle remaining cheese evenly over meatballs and return to oven until meatballs are cooked through, about 15 more minutes.
To brown cheese, place under broiler for a few minutes. Enjoy!