Wash and dry the tomatoes, cut off the tops and scoop out the seeds.
Cook the mushrooms gently in a saucepan with the olive oil. Season them, add the chopped parsley, then remove from the heat.
Mix together the mushrooms and parsley with the rice, eggs, cheese, basil and garlic. Season to taste. Stuff the tomatoes with this mixture then place on an oiled roasting pan in a preheated oven, 180°C (350°F), Gas Mark 4, for around 30 minutes.