To prepare the roasted tomatoes: Take the baby plum/cherry tomatoes and place in a small baking dish. Drizzle with one tablespoon of the olive oil and season well with salt and black pepper. We will roast these later on once the risotto has started cooking.
To make the risotto: Heat the other tablespoon of olive oil in a large pan (I'd recommending using a frying pan). Over a medium to high heat sauté the onion and garlic for a 2-3 minutes until softened. Season well with salt and black pepper.
Now add the risotto rice to the pan and toast over the heat for another minute.
In a large jug mix together the pasatta and vegetable stock until combined. Turn the heat down slightly and add a ladel of the tomato/stock liquid to the risotto. Keep adding the liquid bit by bit until it's absorbed, stirrring well in between each addition.
Once the risotto has been cooking for about 10 minutes, pop the tomatoes you prepared earlier in the oven at 200°C / 180°C Fan / 400°F / Gas Mark 6. Roast the tomatoes for 15-20 minutes. Once they're ready, take out from the oven ready for later.
Cook the risotto for roughly 25-30 minutes or until the rice is cooked through, add more boiling water or stock to get the consistency as you desire.
Once the risotto rice is cooked, add 3/4 of the roasted tomatoes and stir through. Serve the risotto in a large bowl or seperate bowls, garnish with the remaining roasted tomatoes and fresh basil leaves.