1. Make the butternut noodles by using a spiralizer or a julienne peeler. You should get a big pile of noodles if you’re using a large-ish squash. If you’re using a spiralizer, remember to break up the noodles so they aren’t extra long.
2. Heat a thin layer of olive oil in a large, high-sided frying pan/skillet over a medium-high heat. Add the mushrooms, half of the garlic, and a good pinch of salt. Cook, stirring only a couple of times, for about five to six minutes, until softened and golden. Stir in a pinch of the chopped sage leaves (leaving most of them for later). Remove the mushrooms from the pan and set aside.
3. Heat another thin layer of olive oil over a medium-high heat. Add the butternut noodles, remaining garlic and another couple of pinches of salt and stir. Cook for about two minutes, stirring once or twice.
4. Add a little splash (just a tablespoon or two) of water and cover the pan. Cook for another three to four minutes, until the butternut is tender.
5. Stir in the remaining sage and the mushrooms until everything is well combined. Taste for seasoning, adding more salt if needed and a crack of black pepper.
6. Serve divided between two bowls and topped with toasted walnuts and another drizzle of olive oil.
Deseed the bottom hollowed-out part, cut into pieces, and roast at 220 degrees Celsius (425 degrees Fahrenheit)/Gas 7 for about 30 minutes. Add to salads, bowls or a savory porridge.