Creating Cheesy French Onion Meatballs is a fun and straightforward endeavor. Follow these steps carefully to achieve fantastic results:

1. Preheat the Oven: Preheat your oven to 400°F (200°C) and prepare a baking sheet lined with parchment paper.
2. Caramelize the Onions: In a skillet over medium heat, add 2 tablespoons of olive oil. Add the finely chopped onion and cook until golden brown, about 10-15 minutes. Stir occasionally to avoid burning.
3. Add Garlic: Once the onions are caramelized, add minced garlic and cook for an additional 1-2 minutes until fragrant. Remove from heat and let cool slightly.
4. Mix Ingredients: In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, Gruyère cheese, egg, Worcestershire sauce, thyme, salt, and pepper. Add the cooled onion and garlic mixture.
5. Shape Meatballs: Using your hands, mix thoroughly until everything is evenly incorporated. Shape the mixture into meatballs, about 1 inch in diameter, and place them on the prepared baking sheet.
6. Bake: Bake the meatballs in the preheated oven for about 20-25 minutes, or until cooked through and browned on the outside.
7. Add Cheese Topping: In the last 5 minutes of cooking, sprinkle additional Gruyère cheese on top of the meatballs.
8. Garnish: Remove from the oven, and let cool slightly before garnishing with fresh parsley.

These step-by-step instructions will guide you in preparing Cheesy French Onion Meatballs effortlessly!