Preheat oven (electric cooker: 200 °C/circulating air: 180 °C/gas: see manufacturer). Put tomatoes, cream and pesto into a high mixing bowl, puree finely, season with salt and pepper. Heat up the sauce. Clean, wash and dice the peppers. Drain the corn.
Spread the tortelloni, peppers and corn in an ovenproof dish. Pour hot sauce evenly over the top and cook in a hot oven for about 15 minutes. Dice mozzarella finely. Wash basil, pluck leaves and chop. After about 5 minutes, spread the mozzarella and basil on the gratin and gratinate.