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. Lie the pastry strips around the edges of the tart bases.
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.
While your tart bases are baking, prep your tomatoes by cutting some in half. Toss with olive oil, salt and pepper.
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.
