Lay torn strips of prosciutto under the peppers and scatter the baked tart with toasted pine nuts.
Put a baking sheet in the oven and preheat to fan 200C/conventional 220C/gas 7. (Heating the sheet helps cook the pastry base.) Use the pastry to line a shallow rectangular tin about 20 x 30cm. Prick the base lightly with a fork.
Scatter the Parmesan over the pastry base. Drain the peppers and pat dry on paper towels. (If the peppers are in oil, don’t worry about this part.) Lay the whole peppers widthways across the pastry base. If the peppers aren’t in oil, brush a little over them and the pastry, then season. Bake for about 15 minutes until the pastry is puffy and golden.
Slice the tomatoes and mozzarella. Lay alternating, slightly overlapping lines of tomato and mozzarella over the peppers. Drizzle with oil, scatter with basil leaves and an extra grinding of black pepper, then serve while the pastry is still warm.