In a large skillet, melt 2 tablespoons of butter and add 1 tablespoon of olive oil over medium heat. Stir in the freshly sliced onions, a few sprigs of thyme, and a bay leaf. Cook on low, stirring every 10 minutes for about 45 minutes, until the onions are deeply caramelized, shiny, and fragrant, transforming into a golden-brown delight.

Increase the heat to medium-high and pour in 1/2 cup of white wine, scraping the bottom of the pan to release the flavorful bits. Let it boil for about 3 minutes to evaporate the alcohol, then add 6 cups of high-quality beef broth. Bring the mixture back to a gentle boil, lower the heat to simmer, and season to taste with salt and pepper for your Easy French Onion Soup.

While the soup simmers, preheat your broiler. Ladle the hot soup into oven-safe bowls, ensuring each bowl has plenty of those sweet caramelized onions. Place a toasted baguette slice on top of the soup in each bowl and generously sprinkle about 1 cup of grated Gruyère cheese over the bread.

Transfer the bowls to a baking sheet and place them under the broiler for 3-5 minutes, watching closely as the cheese melts and bubbles. Remove the bowls from the oven once the cheese turns golden and starts to brown.

Optional: Add a few fresh thyme leaves on top for a pop of color and extra flavor. Serve your Easy French Onion Soup immediately.