Heat the oven until it has reached 200 degrees (Celsius).
Dice the pumpkin and place in the oven in a roasting dish. Roast until soft (but still holding its shape - it will need to be stirred into the risotto so you don't want it to turn to mush). This should take around 25-30 minutes.
Gently heat the chicken stock, wine, saffron strands and bay leaf in a saucepan until simmering.
In a large frypan heat the butter until melted and slightly bubbling. Add the garlic, onion and lemon zest and cook over a medium heat until the onion is soft and translucent. Don't allow it to burn.
Add the rice and stir to coat it in the mixture already in the pan for about 2 minutes.
Add the stock/wine mixture one ladleful at a time. Stir constantly and add more of the stock as the rice soaks it up. Keep doing this until the rice is cooked and the stock has been used.
Add the roast pumpkin and lemon juice, and stir until combined.
Then, add the chopped basil and stir through until just wilted.
Finally, top with ground black pepper and the grated parmesan and serve with crusty french bread (and maybe a salad).