01 - Preheat the oven to 400°F. Lightly grease a mini muffin tin to prevent sticking.
02 - Cut the thawed puff pastry into 12 equal squares and press each square into the cavities of the mini muffin tin.
03 - Place a spoonful of caramelized onions into each pastry-lined cavity and drizzle with a small splash of broth.
04 - Distribute shredded Gruyère cheese evenly on top of each bite.
05 - Transfer the muffin tin to the oven and bake for 12 to 15 minutes, or until the pastry is golden and the cheese is bubbly.