French Onion Meatballs

Ingredients:

For the onions

2 tablespoons olive oil

4 medium yellow onions, thinly sliced (about 6 cups)

3 cloves garlic, thinly sliced

2 bay leaves

1 1/2 teaspoons kosher salt

1 teaspoon fresh thyme leaves

1/2 teaspoon freshly ground black pepper

1/3 cup dry white wine, such as sauvignon blanc

2 tablespoons unsalted butter

For the meatballs

1 pound 90% lean ground beef

1 large egg, beaten

1/3 cup panko breadcrumbs

1 teaspoon kosher salt

1/2 teaspoon freshly ground black pepper

2 tablespoons olive oil

For the sauce and serving

1 tablespoon all-purpose flour

2 cups low-sodium chicken broth

1 teaspoon Dijon mustard

1 teaspoon Worcestershire sauce

6 ounces freshly grated Gruyere cheese (about 1 cup)

Toasted baguette slices, for serving

 Method:

Cook the onions:

In a large skillet, heat the olive oil over medium heat. Add the onions, garlic, bay leaves, and salt and cook, stirring frequently, until the onions are deeply golden (but not quite caramelized) and reduced significantly in volume, about 45 minutes. You can add a splash or two of water to the pan if it starts to become dry (this tends to happen around the 30-minute mark). 

Add the thyme and black pepper and cook until the herbs are fragrant, about 1 minute. Add the white wine and butter, scraping up the bottom of the pan to loosen any dark bits. Remove and discard the bay leaves and transfer the onions to a plate to let cool slightly. Rinse and wipe out the skillet and set aside.

Make the meatball mixture:

In a large bowl, combine the ground beef, egg, panko, salt, and pepper. Once the onions are cool enough to handle, roughly chop half the onions and add them to the meatball mixture. 

Use your clean hands to mix everything together until combined.

Form the meatballs:

Divide the mixture up into 16 roughly 1 1/2-inch balls. A foolproof way to do this is by forming the meat mixture into an even mound, dividing the mound into quarters, and dividing each quarter into quarters again.

Cook the meatballs:

Heat 2 tablespoons of olive oil in the reserved skillet over medium-high heat. Add the meatballs, making sure to space them evenly, and cook until browned on all sides, 10 to 12 minutes. 

Sprinkle flour over the meatballs and toss gently until the flour is cooked, about 1 minute. Add the chicken broth, remaining reserved onions, mustard, and Worcestershire. Stir well, and let simmer until the sauce has thickened and grown slightly darker in color, about 10 minutes.

Add the cheese and broil:

Preheat the broiler on low. Sprinkle the Gruyere over the meatballs and sauce and broil until the cheese is melted, about 2 minutes. 

Serve with toasted baguette slices. Leftover meatballs and sauce will keep for up to 5 days in the fridge.