This French onion grilled cheese is the ultimate grown up grilled cheese. With a layers of Gruyere Cheese and Creamy French Onions on top sourdough bread you will be making this on repeat.
In a skillet add butter. Once hot and melted, add the onions, salt and pepper. Allow them to cook over medium low heat until deeply caramelize for about 20 to 25 minutes, stirring frequently, until the onions become very dark, soft and jammy.
Add in the garlic, wine, balsamic, and Worcestershire. Allow the French onion sauce to simmer to 5 minutes until thickened.
Butter one side of each slice of bread. Add to a skillet over medium heat and layer shredded cheese, French onions, more shredded cheese, and another slice of bread with butter side facing up.
Cook until the bread has browned (about 2-4 minutes) and then flip.
You can cover the skillet with a lid or place into a preheated oven if you need help getting the cheese to melt.