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 puff pastry crust. It’s a perfect centerpiece for any meal, whether it’s a cozy dinner or a festive gathering.
For more savory tart ideas, check out this Tomato Tarte Tatin or this Easy Ricotta Tomato Tart.
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 teaspoon fresh thyme leaves
- Salt and pepper to taste
- 1 egg, beaten (for egg wash)
Step-by-Step Instructions
1. Caramelize the Onions
Heat olive oil and butter in a pan over medium heat. Add the sliced onions and cook until soft and translucent. Sprinkle with sugar and continue cooking until the onions are golden brown and caramelized. Stir in the thyme leaves and season with salt and pepper. Set aside to cool.
2. Prepare the Puff Pastry
Roll out the thawed puff pastry on a lightly floured surface. Transfer it to a parchment-lined baking sheet. Using a sharp knife, score a border about 1 inch from the edge of the pastry, being careful not to cut all the way through.
3. Assemble the Tart
Spread the caramelized onions evenly over the pastry, staying within the scored border. Arrange the beefsteak tomato slices on top of the onions, slightly overlapping them. Season the tomatoes with salt and pepper.
4. Bake the Tart
Brush the edges of the pastry with the beaten egg. Bake in a preheated oven at 375°F (190°C) for 25-30 minutes, or until the pastry is golden brown and puffed.
5. Serve
Allow the tart to cool slightly before slicing. Garnish with additional thyme leaves if desired. Serve warm or at room temperature.
Expert Tips
- For extra flavor, sprinkle grated Parmesan cheese over the caramelized onions before adding the tomatoes.
- To prevent a soggy crust, pat the tomato slices dry with a paper towel before placing them on the tart.
- This tart can be served as a main dish with a side salad or as an appetizer for a larger meal.
FAQ
Can I use other types of tomatoes?
Yes, you can use heirloom tomatoes or large vine-ripened tomatoes as a substitute for beefsteak tomatoes.
How do I store leftovers?
Store any leftovers in an airtight container in the refrigerator for up to 2 days. Reheat in the oven at 350°F (175°C) for about 10 minutes.
Can I make this tart ahead of time?
Yes, you can assemble the tart and refrigerate it for up to 2 hours before baking. This makes it a great option for entertaining.
For more delicious recipes, explore our Cherry Tomato Tart with Herbed Ricotta or this Easy Rustic Tomato Cheese Tart.

Beefsteak Tomato Tart with Caramelized Onions & Thyme
Ingredients
Method
- Heat olive oil and butter in a pan over medium heat. Add the sliced onions and cook until soft and translucent. Sprinkle with sugar and continue cooking until the onions are golden brown and caramelized. Stir in the thyme leaves and season with salt and pepper. Set aside to cool.
- Roll out the thawed puff pastry on a lightly floured surface. Transfer it to a parchment-lined baking sheet. Using a sharp knife, score a border about 1 inch from the edge of the pastry, being careful not to cut all the way through.
- Spread the caramelized onions evenly over the pastry, staying within the scored border. Arrange the beefsteak tomato slices on top of the onions, slightly overlapping them. Season the tomatoes with salt and pepper.
- Brush the edges of the pastry with the beaten egg. Bake in a preheated oven at 375°F (190°C) for 25-30 minutes, or until the pastry is golden brown and puffed.
- Allow the tart to cool slightly before slicing. Garnish with additional thyme leaves if desired. Serve warm or at room temperature.






