Ingredients
Method
Instructions
- Heat the olive oil and butter in a large skillet over medium heat. Add the sliced onions and cook, stirring occasionally, until they begin to soften. Sprinkle with sugar and continue cooking, stirring frequently, until the onions are golden brown and caramelized. This should take about 20-25 minutes. Stir in the thyme leaves and season with salt and pepper. Set aside to cool.
- Preheat your oven to 400°F (200°C). Roll out the thawed puff pastry on a lightly floured surface to fit your tart pan or baking sheet. Transfer the pastry to the pan and prick the bottom with a fork to prevent it from puffing up too much during baking.
- Spread the caramelized onions evenly over the puff pastry, leaving a small border around the edges. Arrange the beefsteak tomato slices on top of the onions, slightly overlapping them. Sprinkle with grated Gruyère cheese if using.
- Bake in the preheated oven for 20-25 minutes, or until the pastry is golden brown and the tomatoes are tender. Remove from the oven and let it cool slightly before slicing and serving.
Notes
Choose ripe but firm beefsteak tomatoes for the best flavor. Thinly and evenly sliced onions will caramelize more uniformly. To avoid a soggy crust, blind bake the puff pastry for 10 minutes before adding the toppings. Adding Gruyère cheese enhances the tart with a nutty and creamy flavor.
