Tip the squash into a large microwavable bowl with 4 tbsp water and season. Cover with a microwaveable plate or lid and microwave for 12-15 mins or until very tender.

Meanwhile, tip the butter into a frying pan and melt over a medium heat. Allow to cook for 2-3 mins until golden brown with a biscuity smell. Add the whole sage leaves for the last minute to crisp up. Remove and set aside.

Crush the cooked squash with a potato masher and stir though most of the brown butter, the chopped sage, the nutmeg and a generous pinch of salt. Drizzle over the remaining butter and scatter with the hazelnuts and crispy whole sage leaves.