Preheat the oven to 350°F or 180°C. Add the cubed pumpkin, white onion and garlic to a tray and cover with olive oil. Roast for about 30 minutes or until the pumpkin is fork tender. Let cool before slightly blending to a thick paste. Set aside.
For the fried sage, warm up some olive oil in a pan and gently lower in the sage leaves. Fry in the oil until crispy for about 1 minute on each side.
In a large pot, cook the pasta until al dente in salted water according to the instructions on the package.
While the pasta is cooking, add the pumpkin purée to a pan and heat up. Add the nutmeg and chili flakes. Season with salt and pepper to taste. Let cook for a few minutes.
Once the pasta is almost cooked, take 2 tablespoons of pasta water and add it to the sauce. Stir immediately. As soon as the pasta is cooked transfer it to the pan. Mix completely until all the pasta is covered in the pumpkin sauce.
Serve immediately with a few leaves of fried sage and a sprinkle of almond dukkah. Enjoy!