01 -
Heat oven to 210°C / 410°F. Cut squash into 1.5 cm cubes, toss with 1 tablespoon oil and half the sage, then roast on a tray for 25–30 minutes until tender and lightly browned.
02 -
Keep vegetable broth hot in a saucepan at a very gentle simmer. Heat remaining oil and 15 g butter in a wide heavy pan. Cook onion for 5 minutes until soft.
03 -
Add arborio rice and stir for 1–2 minutes until the grains look glossy. Add a ladle of hot broth and stir gently.
04 -
Keep adding broth a ladle at a time as each addition is mostly absorbed, stirring frequently. Cook for about 18–22 minutes until rice is tender with a slight bite; you may not need all the broth.
05 -
Mash about a third of the roasted squash and stir into the rice with the remaining sage and pepper. Fold in the remaining squash cubes gently.
06 -
Take off the heat and stir in the remaining butter and Parmesan. Add a little more hot broth if needed so the risotto flows gently rather than standing stiff. Cover for 3 minutes and serve promptly.
07 -
Cool leftovers promptly in shallow containers and refrigerate within two hours for up to two days. Reheat thoroughly with extra broth or water; the rice will soften further.