Preheat oven to 400°F. On a floured surface, roll out pastry sheet. Transfer to a sheet pan. Score the edges of the pastry sheet – this will help it to puff up as it bakes and produce a crust.
Spread the red pepper pesto onto the pastry. Arrange tomatoes on the pesto with the cut-side facing up. Whisk together the olive oil and harissa paste, and drizzle over the tomatoes.
Bake the tart for 15 minutes, or until pastry is golden. Sprinkle with fresh or dried cilantro.
*Note: To make harissa paste, combine 3 Tbsp Harissa Blend with 2 Tbsp olive oil, stirring together to make a thick paste.