Preheat the oven to 425˚, or an air fryer to 400˚

Defrost puff pastry according to package directions. Roll out puff pastry to barely overlap a full sheet pan (26.5 by 18.5 inches) or split the dough in half and use two half sheet pans, rolling out dough to barely overlap pans (18.5 by 13.5 inches).

Cut along the edges of the sheet of dough to create a separation from the flat bottom and the sides. Lightly pierce the dough with the tines of a fork. Spread the pesto over the bottom, and lay tomato slices with at least 1 inch of space between tomatoes. Season the tops of the tomatoes with salt, black pepper, and red pepper flakes.  Place in oven for 20-30 minutes, until the dough has browned and edges are crispy. Let cool for 5 minutes before cutting.

Serve as an appetizer or with a side salad for a perfect meal.‍