1 small onion, finely chopped
4 small pumpkins, tops cut off about a fifth of the way down and insides scooped out and discarded (remove the seeds and stringy flesh but leave in the tender outer flesh)
200g/7oz pumpkin flesh (skin removed), finely diced
125g/4½oz risotto rice, such as Arborio rice
850ml/1½ pint chicken or vegetable stock (or as much as needed)
sea salt and freshly ground black pepper
2 tbsp olive oil, plus extra for drizzling
50²µ/1¾´Ç³ú pistachio nuts
50²µ/1¾´Ç³ú unsalted butter
100²µ/3½´Ç³ú pecorino cheese (or alternative vegetarian hard cheese) , finely grated, plus extra to serve