Caramelized Onion Pie
A rich, savory tart featuring slow-cooked, golden onions nestled in a buttery, flaky crust with a hint of fresh thyme.
Ingredients
- •1 sheet store-bought puff pastry, thawed
- •4 large yellow onions, thinly sliced
- •3 tablespoons unsalted butter
- •1 tablespoon olive oil
- •1 teaspoon fresh thyme leaves
- •1/2 cup shredded Gruyère or Swiss cheese
- •1 large egg, beaten (for egg wash)
- •1/2 teaspoon salt
- •1/4 teaspoon black pepper
Instructions
- 1
Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
- 2
In a large skillet, melt the butter with the olive oil over medium heat. Add the sliced onions and cook, stirring occasionally, for about 30-40 minutes until they are deeply golden brown and caramelized.
- 3
Stir the thyme, salt, and pepper into the onions, then remove from heat and let them cool slightly.
- 4
Roll out the puff pastry onto the prepared baking sheet. Score a 1-inch border around the edges with a knife, being careful not to cut all the way through.
- 5
Prick the center of the pastry multiple times with a fork to prevent it from puffing up too much in the middle.
- 6
Spread the caramelized onions evenly over the center of the pastry, staying within the border.
- 7
Sprinkle the shredded cheese over the onion layer.
- 8
Brush the edges of the pastry with the beaten egg wash.
- 9
Bake for 15-20 minutes, or until the pastry is golden brown and crispy and the cheese is melted and bubbling.
💡 Chef tips
- For deeper flavor, add a splash of balsamic vinegar to the onions during the last 5 minutes of caramelization.
- You can prepare the caramelized onions up to two days in advance and keep them refrigerated until you are ready to assemble the pie.
- If you prefer a dairy-free version, substitute the butter with olive oil and the cheese with a plant-based alternative or toasted pine nuts.
✅ How it should turn out
The finished pie should have a perfectly crisp, golden-brown crust with a sweet, jammy onion filling that smells fragrant and savory.