Prepare the onions - Peel and thinly slice the yellow onions. Heat the butter in a large soup pot over medium heat. Add the onions and cook until caramelized, stirring occasionally, for about 30 minutes. This slow cooking process will bring out their natural sweetness and deepen the flavor. Be patient, it's worth the wait! - If you prefer a more pronounced onion flavor and darker color, you can cook the onions for an additional 10-15 minutes. Just be cautious not to let them burn.

Simmer the soup - Pour the beef broth into the pot with the caramelized onions. Add the chopped fresh thyme, salt, and black pepper. Increase the heat to medium-high and bring the mixture to a boil. Then, reduce the heat to low and let it simmer for 15 minutes. This allows the flavors to meld together and creates a wonderfully fragrant and flavorful base for your French Onion Soup Ramen.

Cook the ramen noodles - While the soup is simmering, cook the ramen noodles according to the package instructions. Drain and set aside. Note that some ramen noodles may require a shorter cooking time, so adjust accordingly. - If you prefer a gluten-free option or want to switch things up, you can use rice noodles or gluten-free ramen noodles instead. Just follow the cooking instructions on the package.

Prepare the cheesy topping - While the soup is still simmering, preheat your oven's broiler. Place the oven-safe crocks or bowls on a baking sheet. Fill each crock or bowl with a portion of cooked ramen noodles, ladle the soup over the noodles, and top generously with shredded Gruyère cheese. Place the baking sheet with the crocks or bowls under the broiler until the cheese is melted and bubbly, with a golden brown crust.

Serve and enjoy - Carefully remove the crocks or bowls from the oven and allow them to cool slightly. Garnish with fresh thyme leaves if desired. Serve the French Onion Soup Ramen hot and bubbling, accompanied by a baguette or crusty bread for dipping and savor every comforting bite!