Boil the rice, drain and put into a mixing bowl. Add 2 teaspoons of the pesto sauce to the ricotta and mash with a fork. Then add to the warm rice together with the cooked peas, the butter and the grated cheese. Season with salt and pepper.
Brush the inside of 4 individual moulds (or 1 large one) with melted butter or oil. Divide the rice into the moulds, slightly press down with the back of a spoon and when the rice is completely cooled down, un-mould into serving plates and decorate with some pesto sauce, more peas and slices of tomato.