Juicy cherry or grape tomatoes are coated in a light caramel to make the “topping” for this tart, but the whole thing is baked upside down in a skillet. Do most of the steps to prepare it in advance—make the zucchini paste and defrost the puff pastry a few hours or up to two days ahead—but be sure to serve the tart just after baking, turning it out from the pan in front of guests. It tastes best while the caramel is still runny and the warm, topmost layer of dough has a custardy consistency.
For the zucchini paste:
- 1⁄4 cup plus 3 Tbsp. extra-virgin olive oil
- 1⁄4 cup plus 3 Tbsp. honey
- 1 lb. 10 oz. medium zucchini, cut into 1-inch cubes
- A large handful (½ packed cup) mixed herbs, such as basil and parsley
For the tart:
- 50 ripe red or golden cherry or grape tomatoes (1 lb.)
- Olive oil, for drizzling
- Pinch salt, plus more for seasoning
- Pinch sugar
- 1 sheet frozen puff pastry, thawed in the refrigerator
- Small basil or mint leaves, for garnish
- For the caramel:
- 4 tbsp. cold unsalted butter (2 oz.), cut into 1-inch cubes
- 1⁄3 cup castor or superfine sugar (2 oz.)
- Up to 2 days ahead, make the zucchini paste: Preheat the oven to 350°. In a 6-quart Dutch oven, whisk the oil and honey until combined. Add the zucchini and herbs, and season with salt; toss to combine.
- Cut a parchment-paper round to fit inside the pot, and place it atop the zucchini mixture. Cover the pot with a tight-fitting lid and bake until the zucchini is soft and sweet, about 4 hours.
- Remove the mixture to a strainer; drain off and discard about ⅔ cup of the liquid. Transfer the remaining mixture into a small food processor and process until very smooth, 2–3 minutes. Cover and refrigerate if not using immediately.
- Prepare the tomatoes: Set a pot of water to boil, then prepare a bowl of ice water. Using a paring knife, slice a small X into each tomato. Once all the tomatoes are ready, transfer them to the pot of boiling water; let cook until the skins start to pull away from the flesh where cut, about 20 seconds. Remove with a spider or slotted spoon and transfer to the ice water. Once cool enough to handle, peel the tomatoes. Discard the skins or save for another use.
- Transfer the tomatoes to a medium bowl. Add a drizzle of olive oil and a small pinch each of salt and sugar, and toss to coat.
- Two hours before serving, preheat the oven to 350°. Bake the tomatoes to dry slightly, about 1 hour. Remove and increase the heat to 375°. Set a rack in the top third of the oven.
- Make the caramel: Set the butter cubes and a whisk next to the stove. In a 9-inch stainless-steel skillet, add the sugar. Place over medium heat and cook, swirling the pan occasionally, until the sugar has melted and turned deep golden brown. Quickly whisk in the butter until incorporated, then remove from the heat.
- Assemble and bake the tart: Tightly pack the tomatoes in an orderly circular pattern on top of the caramel all around the skillet; season lightly with salt and set aside.
- Cut the puff pastry into a 9½-inch round. Spread about 2 tablespoons of the zucchini paste across one side of the pastry disk, leaving a ½-inch border around the edges. Place the disk with its paste-covered side facing down atop the tomatoes. Tuck the edges around the tomatoes so the dough touches the sides of the pan. Using a paring knife, score the top of the puff pastry in a few places so steam can escape while baking.
- Transfer the skillet to the oven and bake until the pastry is puffed up and deep golden, 28–34 minutes. Open the oven door and let the tart stand 2–3 minutes.
- Overturn a flat serving plate atop the skillet, then quickly invert the skillet to turn the tart out onto the plate. (If any tomatoes remain stuck to the pan, dislodge them and place back on the tart). Let cool slightly. Garnish with basil or mint leaves, slice, and serve.