Place the pumpkin on a sheet pan with the head of garlic and drizzle with oil, salt and pepper and roughly rub the rosemary over the veggies and roast for 30 minutes at 200C
10 mins before the pumpkin is ready boil the pasta in a large saucepan with salted water
Pan fry the mushrooms until just tender and toss in the spinach, sage and nutmeg and heat through until wilted and aromatic
Blend the cooked pumpkin in a food processor squeezing in the roasted bulbs of garlic carefully and add the stock to make a lose but smooth puree
Drain the pasta and toss the puree and pasta back into the saucepan and add the mushrooms and spinach and heat gently making sure everything is coated really well with the sauce and season to taste
Serve with parmesan and a sprinkling of chopped walnuts