Ingredients
Equipment
Method
Preparation Steps
- Slice the yellow onions thinly to ensure even cooking and optimal sweetness.
- Melt butter over medium heat in a large skillet and add onions, salt, and sugar. Cook on low for 30-40 minutes until golden brown.
- Roll out the puff pastry on a clean surface, about an inch larger than the skillet's diameter.
- Optionally, stir in balsamic vinegar to the caramelized onions and cook for an additional minute.
- Layer caramelized onions in the skillet, sprinkle thyme and Gruyère cheese on top.
- Top with prepared puff pastry, pressing edges down to seal.
- Preheat oven to 375°F (190°C) and bake for 20-25 minutes until puff pastry is golden.
- Let cool for 5 minutes, then invert to serve.
Nutrition
Notes
For best results, follow the expert tips on onion selection, caramelization, and egg wash application.
