Making this upside-down tomato tart with cheese is so worth it and a recipe you should keep in your arsenal for every tomato season. It takes a little work, but the end result of this tomato tart tartin is absolutely divine; flavorful caramelized soft tomatoes on a thin layer of cheese with a crispy puff pastry bottom.
Preheat an oven to 400 degrees F. Allow 1 sheet of pastry dough to thaw on your counter.
Add vinegar, sugar, salt & pepper to a oven-safe skillet and simmer swirl until sugar dissolves and it becomes a little thicker, something like a syrup.
Then add the shallot, butter and thyme to the skillet and swirl again until butter is melted and fully incorporated. Take pan off the heat.
Cut the tomatoes in halve, lengthwise and take seeds, the gel and the core out. Try to get rid of as much liquid as possible. No need to peel the tomatoes.
Add the tomatoes to the skillet (NOTE 1) with the vinegar/sugar syrup and gently coat the tomatoes. Make sure all tomatoes face, cut side up, next to each other. Push the as tightly together as you can, as they will shrink, but don't overlap them too much. Sprinkle with a little bit of salt & pepper.
Transfer skillet to your oven and cook them for about 1 hour. Most or all liquid has evaporated and the tomatoes show slightly browned edges. They are soft, but do not collapse.
While the tomatoes cook, prepare your pastry bottom.
Roll the pastry into a circle that is a little bigger than your skillet. Transfer it to a plate and store in the fridge until the tomatoes are cooked.
Remove the skillet from the oven. Mix the grated cheese and divide the mixture over the tomatoes. Top the cheese with the pastry round and return the skillet into the oven.
Bake the tart for about 15 minutes or until puffy and brown. Take the skillet out of the oven and allow to cool for a few minutes.
Place a plate (bottom up) over the skillet and invert the tart onto the plate in one swift move.
Serve warm or cooled.
Notes
The skillet you use is going into the oven, so select the right one. And have pot holders ready.