Photo by Michael Piazza

Submitted by Gayle Squires of Central Square, Cambridge. She buys her tomatoes at the Central Square Farmers Market, and finds her copy of Edible Boston at Russo’s.

"This tarte is based on a recipe that Melissa Clark wrote for her column in the New York Times back in 2008, a couple of tomato tarte tatin recipes in Tamasin Day-Lewis’ The Art of the Tart, and one served at Tatte’s newly-opened Cambridge café. While tarte tatins are traditionally dessert fare, made with apples, this tarte is a combination of sweet and savory as the caramel is spiked with sweet-acidic balsamic vinegar. Throw some crumbled feta or goat cheese on top if you like."

Serves 6-8

1 package frozen puff pastry
2 tablespoons olive oil
3 red onions, sliced
Kosher salt and freshly ground black pepper
¼ cup plus a pinch of sugar
1 tablespoon balsamic vinegar
1 pound cherry or grape tomatoes (or a variety)
1 tablespoon chopped fresh thyme

Defrost the puff pastry for 20-30 minutes on the counter or overnight in the refrigerator. Preheat the oven to 425°.

Heat the olive oil in a skillet over medium heat. Add the onions, some salt + pepper to taste, and a pinch of sugar and sauté until they are golden and caramelized, about 15-20 minutes. Add 2 tablespoons water and scrape the brown bits off the bottom of the pan. When the water cooks off, transfer the onions to a bowl.

To make the caramel, combine ¼ cup sugar and 3 tablespoons water in an ovenproof 9 or 10-inch pan or enameled skillet (preferably with a handle). Cook over medium heat, swirling the pan gently (do not stir: only swirl! Stirring could result in a grainy, crystallized caramel). Watch the sugar very closely—the moment it starts to turn light golden brown, remove it from the heat to avoid burning. Turn on the overhead fan, add the balsamic and continue swirling until the vinegar mixes with the caramel (be aware that the fumes from the vinegar can be very strong!).

Scatter the tomatoes onto the caramel, then sprinkle with the onions, thyme, salt, and pepper. Roll out the puff pastry into a circle about 1 inch larger than the diameter of your pan and transfer the pastry to cover the tomatoes. Tuck edges under and cut several long vents in the pastry.

Bake the tart until the crust if puffed and golden, about 30 minutes. Let stand an additional 30 minutes before running a knife around the edge of the pan to loosen the pastry, and turning it out onto a platter. Cut into wedges and serve immediately. After a few hours the crust will get soggy, so be sure to serve and eat the whole tart at once.