Ingredients
1 sheet puff pastry, thawed
2 large Vidalia onions, thinly sliced
2 tablespoons unsalted butter
1/2 cup beef stock
1 teaspoon fresh thyme leaves (or 1/2 teaspoon dried thyme)
1/4 cup grated Gruyère or Swiss cheese
Salt and pepper to taste
1 egg, beaten (for egg wash)
Instructions
Preheat the oven: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
Prepare the onions: In a large skillet, melt the butter over medium heat. Add the sliced onions and a pinch of salt. Cook, stirring occasionally, for 15-20 minutes, until the onions are caramelized and golden brown. Add the beef stock and thyme, cooking until the liquid is mostly evaporated. Remove from heat and let cool slightly.
Prepare the puff pastry: Roll out the puff pastry on a lightly floured surface to smooth any creases. Place it on the prepared baking sheet. Using a knife, lightly score a 1-inch border around the edges of the pastry (do not cut through).
Assemble the tart: Spread the caramelized onions evenly over the center of the puff pastry, leaving the border clean. Sprinkle grated Gruyère cheese on top of the onions.
Apply the egg wash: Brush the border of the pastry with the beaten egg.
Bake: Bake in the preheated oven for 20-25 minutes, or until the pastry is golden and puffed.
Serve: Let the tart cool slightly before slicing and serving.
This French Onion Tart is a simple yet elegant addition to your holiday table!
