Preheat your oven to 200 degrees Celsius (400 F)/
Cut one of your pastry sheets in half. Cut the second sheet into thin strips (approximately 1 cm wide).
Brush the edges of your 2 pastry sheets with a little water. These will be the base of your tarts. Lie the pastry strips around the edges of the tart bases. You should now have two 'tart shells'
Use a fork to prick the base of the tart shells. You want to do this multiple times, all over the base.
Bake the tart shells in the hot oven for 8-10 minutes, until they are puffed and golden brown. When your tart bases come out of the oven, if the centre has puffed up use a fork or spoon to push the base back down, it does not matter if the pastry flakes a bit when you do this.
While your tart bases are baking, prep your tomatoes by cutting some in half. Do this in a variety of ways i.e. through the middle and some lengthways and some leave whole. Place the tomato pieces in a bowl and toss with olive oil, salt and pepper. Tear up your mozzarella.
Top the tart bases with the pesto, the tomatoes and the mozzarella. Return the tarts to the oven and bake for 12-15 minutes until the pastry is browned and tomatoes softened.
Scatter the top of the tarts with pinenuts and finely sliced basil leaves.