Add baking paper to a very large baking sheet pan/tray (make sure it is perfectly flat on the surface).
From 1 puff pastry sheet you’ll be able to make ~6 tarts. Cut the puff pastry into squares.
Add a pinch of oregano straight on the baking paper, then add the oil, balsamic vinegar, slice of tomato and the square of puff pastry.Repeat 6 times.
Bake at 200C for 13-15 minutes.
Once ready, leave the tarts to cool down a bit so the bottom will have time to harden up and it will be easier to flip them.When you flip the tart over, use a flat spatula and gently scoop it up, then flip over.
Notes
Once ready you can add some extra toppings:I drizzled some more balsamic vinager and added a tsp of pesto.Toasted pine nuts or shaved Parmesan cheese would also be lovely.Tip: They are best once warm but still delicious from cold. Eat straight away but if you have left over I have heated up them in the air fryer for 2-3 minutes before serving(you can also use the oven).I prefer them warm, so the pastry is nice and flaky/crispy