UNSALTED BUTTER VIDALIA ONIONS DRY WHITE WINE ALL-PURPOSE FLOUR DIJON MUSTARD WORCESTERSHIRE SAUCE FRESH THYmE CHICKEN BROTH KOSHER SALT & GROUND BLACK PEPPER CHEESY GRUYERE MEATBALLS: NONSTICK COOKING SPRAY LEAN GROUND CHICKEN (OR TURKEY!) PANKO BREADCRUMBS OLIVE OIL HERBS DE PROVENCE fRESH THYME GARLIC LARGE EGG GRUYERE CHEESE KOSHER SALT & GROUND BLACK PEPPER
Add 2 tablespoons of the butter to a large, heavy-bottomed skillet over medium heat. Once melted, add the sliced Vidalia onions, stirring to coat. Cook, stirring occasionally, for 10-12 minutes until softened & browned. The onions shouldn’t require too much attention at this point, this is a great time to begin prepping & rolling meatballs (Steps 3-4).
Once softened, reduce heat to medium-low. Season the onions with 1/2 teaspoon kosher salt, stirring to combine. Continue to cook, stirring occasionally, until tender, fragrant, & deeply browned, 20-30 minutes more. Tip --> Adjust the heat as needed to ensure onions do not burn!
As the onions soften & caramelize, prepare the cheesy gruyère meatballs. Preheat the oven to 400 degrees F. Lightly spray a rimmed baking sheet with nonstick cooking spray. Set aside. Add the panko breadcrumbs, olive oil, herbes de Provence, chopped fresh thyme, garlic, & egg to a medium mixing bowl. Season with 1 teaspoon kosher salt & ground black pepper as desired. Use your hands to mix well. Once the breadcrumb mixture is combined, add in the ground chicken or turkey. Using your hands, mix just until combined – take care to avoid over-mixing.
Divide the meatball mixture into 12-14 equal portions. Working one portion at a time, press the meatball mixture into a flat patty about 2-3 inches wide. Place a cube of gruyère cheese in the center, wrap the edges of the patty around the cheese, forming a meatball with a piece of cheese encased in the center. Be sure to seal the edges tightly, then gently roll into a ball. Place the meatball on the prepared baking sheet & repeat with remaining mixture.
Lightly spritz the meatballs with cooking spray for a golden finish, then transfer the baking sheet to the oven. Bake 15-18 minutes, until cooked through.
Once the onions are caramelized, deglaze the skillet. Slowly pour in the white wine, using a wooden spoon to scrape up any browned bits formed on the bottom of the pan. Increase the heat to medium-high to bring the wine to a simmer, then simmer 4-5 minutes or until reduced completely. Add the flour, Dijon mustard, Worcestershire sauce & thyme to the skillet, stirring to coat the onions, then add in the chicken broth. Bring to a simmer & allow to reduce slightly.
Nestle the baked cheesy gruyère meatballs from Step 5 into the French onion sauce. Spoon some of the onion sauce over top the meatballs. Simmer 5 minutes, stirring & turning the meatballs every so often to ensure they’re nicely coated in the French onion sauce.
Allow to cool slightly, then serve the French onion meatballs over egg noodles, mashed potatoes, or alongside simple green salad. For an extra-special finishing touch, sprinkle toasty garlic herb breadcrumbs over top!