In a large skillet, melt 2 tablespoons of unsalted butter over medium heat. Add 2 sliced yellow onions and cook for 20-25 minutes, stirring occasionally until they turn a deep golden brown and are beautifully caramelized.

Stir in 2 minced garlic cloves and sauté for an additional 1 minute until fragrant. Be careful not to let the garlic burn.

Add 1 cup of long-grain white rice to the skillet with the onions and garlic. Stir for 2-3 minutes to lightly toast the rice.

Pour in 2 cups of beef broth, followed by 1 tablespoon of Worcestershire sauce, 1 teaspoon of dried thyme, a bay leaf, and a sprinkle of salt and pepper. Stir to combine.

Bring the mixture to a gentle boil, then lower the heat to the lowest setting and cover. Let simmer for approximately 18-20 minutes or until the rice is tender.

Remove from heat and fold in 1 cup of grated Gruyère cheese until melted. Discard the bay leaf.

Let the dish sit covered for 5 minutes. Fluff rice with a fork and garnish with chopped parsley. Serve warm.