Gather and prep all ingredients so you’re ready to go.

Place the breadcrumbs into a dish, pour the milk over them and soak for 5 minutes.

Meanwhile, place the ground beef into a large bowl.

After the breadcrumbs have soaked, add them into the ground beef bowl along with chopped parsley, fresh thyme leaves, herbes de Provence, salt, pepper, minced onion, garlic, ¼ cup of the shredded Gruyère and the whisked egg.

Using clean hands, gently mix the beef and ingredients until well combined—avoid over-mixing to keep the meatballs tender.

Scoop out 2-tablespoon portions (a cookie scoop works well) and place them on a tray or platter.

Wet your hands and roll each portion into a round meatball. Chill in the fridge for 15 minutes.

While the meatballs chill, prep the sauce ingredients.

Heat a large oven-safe skillet over medium-high heat with 2 tablespoons of olive oil.

Sear the meatballs in batches, browning them on all sides for about 8–10 minutes. Set aside.

In the same skillet, add more oil if needed, plus the ghee or butter. Sauté the onions with a pinch of salt and pepper for 20–25 minutes until deeply caramelised.

Stir in garlic, herbes de Provence, and dried thyme for 30 seconds. Add sherry or wine and reduce for 30 seconds.

Sprinkle in the flour, stir to incorporate, then pour in beef stock. Stir well and simmer for 5 minutes to thicken.

Preheat your broiler to high.

Stir fresh thyme leaves into the sauce. Gently place the browned meatballs back into the skillet, letting them settle into the rich sauce.

Top the meatballs with the remaining Gruyère and mozzarella cheese. Broil for 5–7 minutes until bubbly and golden.

Garnish with fresh thyme leaves and serve with crusty bread or mashed potatoes.