Preheat the oven to Gas 7 (220C). Cut a slice at the top of the tomatoes and carefully scoop out the flesh and seeds. Chop the flesh and discard the seeds. The skins should be placed into an ovenproof dish.
Heat the oil in a small pan and cook the spring onions for approximately 2 minutes until soft. Stir in the rice and a quarter of the stock and simmer until the liquid has been absorbed by the rice. Add the chopped tomato.
Add the remaining stock, 2 tablespoons at a time, ensuring that the liquid is absorbed before adding any more. When cooked (25 minutes) the rice will be tender and creamy. (You may not need all the stock). Place mixture into a bowl.
Place the pine nuts on a baking tray and cook for 5 minutes. Add these together with the feta cheese and pesto to the rice mixture. Stir to combine and stuff the tomatoes. Bake for 20 minutes and serve garnished with basil.