Preheat the oven to 400˚F.
For a 13 x 4-inch rectangular tart: On a lightly floured surface, lay out the sheet of puff pastry. Dust the surface of the pastry with flour and, using a rolling pin, roll out the pastry another inch vertically and horizontally. Using a knife, cut it in half. Lay 1 half of the sheet into the tart tin so that the base and sides of the tin are lined. With the remaining half, line the rest of the tin pressing the edges of the pieces of pastry together lightly to seal.
For a 9-inch round tart: On a lightly floured surface, roll out the puff pastry another inch in diameter. Line the 9-inch round tart pan.
Prick the base of the puff pastry all over with a fork and place the prepared pan in the refrigerator to chill for 15 – 30 minutes, or until the pastry is cold to the touch.
Once chilled, spread the pesto evenly over the entire surface of the puff pastry. Top with the quartered cherry tomatoes and the feta cheese. Bake in the preheated oven for approximately 25 minutes, or until the pastry is cooked through and has started to pull away from the sides of the tart tin.
Remove from the oven and allow the tart to cool for 5-10 minutes before transferring to a serving plate. Garnish with some torn fresh mint leaves and serve warm.
I like to bake this in a rectangular quiche tin I found a few years ago. If you make a lot of tarts or quiches, you might want to consider investing in one. They are a great way to up your presentation game!