To begin preheat oven to 220°C. Lightly oil a flat baking tray. Next place the onions, tomatoes and peppers on the baking tray, drizzle them lightly with olive oil and roast for 15-20 minutes or until just tender. Allow them to cool slightly. Then lay a pastry sheet on baking paper. Score the pastry with a sharp knife about 1cm from the edge. Spread a layer Saclà Tomato Pesto on the pastry within the scored line. Next top the pastry with the roasted vegetables and mozzarella, brush the borders with the beaten egg and bake for 12-15 minutes, until the borders have risen and are golden brown. The roasted vegetables, tomato pesto and mozzarella make a great Mediterranean medley.