Meatballs should be slightly larger than a golf ball, depending on the size of your ice cube tray. If you don’t have gruyère cheese, other options will work like Mozzarella, Swiss, or Gouda
- Heat a medium pot to medium low with 2 Tbsp of olive oil. Slice 3 onions and transfer to pot.
- Cook until the onions are well browned, approximately 40-50 minutes.
- While the onions are cooking, transfer ground turkey, 1 cup of the panko breadcrumbs, ¼ cup of milk, ½ onion (grated), 3 cloves of garlic, ½ tsp of salt, ¼ tsp pepper, 1 tsp chopped fresh thyme, 2 eggs, and 2 Tbsp grated parmesan cheese to a large bowl and mix until combined. Chill in the fridge.
- When the onions are browned, add 3 cloves of garlic (grated), white wine, and 2 Tbsp of butter and cook for 5 minutes until reduced.
- Add ¼ tsp salt, ⅛ tsp pepper, 1 Tbsp balsamic vinegar, 1 Tbsp chopped fresh thyme, sugar, and flour and stir until flour is no longer visible.
- Add mushroom broth and simmer for 5 minutes.
- Transfer 1 Tbsp of French onion filling to each slot in an ice cube tray and freeze for at least 3 hours.
- For the breadcrumb topping, melt ¼ cup butter in a small pan on medium low heat. Add 1 garlic clove (grated) and cook for 1 minute. Add ¾ panko breadcrumbs, 1 tsp each of thyme and parsley, and 1 Tbsp of parmesan. Stir occasionally until golden brown.
- When you’re ready to assemble, preheat the oven to 400° F and remove your French onion filling from the tray. Form 3 Tbsp of meatball and flatten in your hand. Place French onion filling in the meatball, close up and roll to shape a ball.
- Sear meatballs on medium high heat with 2 Tbsp of vegetable oil. Cook 5 minutes per side.
- Transfer to the oven and bake for 25 minutes until the meatballs reach an internal temperature of 165° F.
- While the meatballs are cooking, grate gruyère cheese. Remove meatballs and top with cheese. Broil for 2-5 minutes until bubbly.
- Serve warm and finish with fresh parsley and breadcrumb topping