These French Onion Stuffed Mushrooms are filled with caramelized onions, melty cheese, and savory herbs—an easy, crowd-pleasing appetizer perfect for any occasion.
Melt butter in a pan over medium heat. Add onions and caramelize for 15 minutes. Add in garlic cloves and continue to caramelize for an additional 3 to 5 minutes.
Stir in beef broth and cook for 2 more minutes.
Add onion mixture to a medium bowl and add in thyme. Add about a tsp of filling to each mushroom and arrange on a baking sheet. Top with cheese and garnish with a little fresh thyme.