Heat the oven to 200°C, 180°C fan, Gas Mark 6. Peel and chop butternut squash, place in a roasting tin, season and drizzle with 1tbsp oil. Roast for about 20 minutes, or til tender. Finely chop half the cooked squash.
Heat 1tbsp oil in a large pan and gently fry chopped onion and finely chopped clove garlic for about 5 minutes. Stir in risotto rice and cook for a minute until the rice becomes translucent then add the finely chopped squash.
Dissolve 1 vegetable stock cube with 1litre of boiling water and add a ladleful to the rice, stir until completely absorbed before adding more. Repeat this, adding stock a ladleful at a time and stirring until the rice is just done. Season, stir in 1tbsp picked fresh thyme leaves, 2tbsp grated Parmesan cheese and the remaining cubes of squash. Put the lid on and leave to stand for a minute before serving.