Beefsteak Tomato Tart with Caramelized Onions & Thyme
Beefsteak Tomato Tart with Caramelized Onions & Thyme

Indulge in the rich flavors of summer with this Beefsteak Tomato Tart with Caramelized Onions & Thyme. This dish combines the sweetness of caramelized onions, the juiciness of beefsteak tomatoes, and the aromatic touch of thyme, all nestled in a flaky, buttery crust. Perfect for a light lunch or a sophisticated dinner, this tart is sure to impress your guests and satisfy your taste buds.
Ingredients

- 1 sheet puff pastry, thawed
- 2 large beefsteak tomatoes, sliced
- 2 large onions, thinly sliced
- 2 tablespoons olive oil
- 1 tablespoon butter
- 1 teaspoon sugar
- 1 tablespoon fresh thyme leaves
- Salt and pepper to taste
- 1 cup shredded mozzarella cheese
- 1/4 cup grated Parmesan cheese
- 1 egg, beaten (for egg wash)
Step-by-Step Instructions
1. Caramelize the Onions
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.
2. Prepare the Puff Pastry
Preheat your oven to 375°F (190°C). Roll out the thawed puff pastry on a lightly floured surface to fit your tart pan. Transfer the pastry to the pan and trim any excess edges. Prick the base of the pastry with a fork to prevent it from puffing up too much during baking.
3. Assemble the Tart
Spread the caramelized onions evenly over the puff pastry. Arrange the beefsteak tomato slices on top of the onions, slightly overlapping them. Sprinkle the shredded mozzarella and grated Parmesan cheese over the tomatoes. Brush the edges of the pastry with the beaten egg to create a golden crust.
4. Bake the Tart
Place the tart in the preheated oven and bake for 25-30 minutes, or until the pastry is golden brown and the cheese is bubbly and lightly browned. Remove from the oven and let it cool for a few minutes before slicing and serving.
Expert Tips
- For extra flavor, you can add a sprinkle of dried oregano or basil to the tart before baking.
- To make the tart even more decadent, drizzle a little balsamic glaze over the top before serving.
- If you prefer a crispier crust, blind bake the puff pastry for 10 minutes before adding the toppings.
- This tart is best served warm but can also be enjoyed at room temperature.
FAQ
Can I use a different type of tomato?
Yes, you can use heirloom tomatoes or large vine-ripened tomatoes if beefsteak tomatoes are not available. However, beefsteak tomatoes are ideal due to their meaty texture and rich flavor.
Can I make this tart ahead of time?
Absolutely! You can assemble the tart and refrigerate it for up to 4 hours before baking. Alternatively, you can bake it ahead of time and reheat it in the oven at 350°F (175°C) for about 10 minutes before serving.
What can I serve with this tart?
This tart pairs beautifully with a simple green salad or a refreshing Peach Tomato Caprese Salad. It also goes well with a bowl of Classic Beef Pot Pie for a heartier meal.
Can I freeze the tart?
Yes, you can freeze the baked tart. Allow it to cool completely, then wrap it tightly in plastic wrap and aluminum foil. Freeze for up to 1 month. To serve, thaw overnight in the refrigerator and reheat in the oven at 350°F (175°C) for about 15 minutes.
Enjoy this delightful Beefsteak Tomato Tart with Caramelized Onions & Thyme as a centerpiece for your next gathering or a special treat for yourself. Its combination of flavors and textures is sure to make it a favorite!

Beefsteak Tomato Tart with Caramelized Onions & Thyme
Ingredients
Method
- 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 375°F (190°C). Roll out the thawed puff pastry on a lightly floured surface to fit your tart pan. Transfer the pastry to the pan and trim any excess edges. Prick the base of the pastry with a fork to prevent it from puffing up too much during baking.
- Spread the caramelized onions evenly over the puff pastry. Arrange the beefsteak tomato slices on top of the onions, slightly overlapping them. Sprinkle the shredded mozzarella and grated Parmesan cheese over the tomatoes. Brush the edges of the pastry with the beaten egg to create a golden crust.
- Place the tart in the preheated oven and bake for 25-30 minutes, or until the pastry is golden brown and the cheese is bubbly and lightly browned. Remove from the oven and let it cool for a few minutes before slicing and serving.






