1. Peel and cut the butternut squash into cubes, and steam for 8 to 10 minutes (cubes must remain firm).
  2. In the meantime, prepare crumble crumbs: mix hazelnut powder, flour, salt and the ZEN granola in a salad bowl. Add the hazelnut butter and mix until a crumbly mixture is obtained. Refrigerate.
  3. Cut the onion into thin slices. In a skillet, heat the olive oil at medium heat, add the onion and sauté until softened.
  4. Preheat the oven to 350°F.
  5. In a food processor, roughly mix the hazelnuts.
  6. Crush the chestnuts in pieces.
  7. Drain the cubes of butternut squash and spread them in a dish with the onions.
  8. Sprinkle with ground nutmeg, salt, pepper, hazelnuts and chestnuts, and cover with crumble crumbs. Put in the oven for 15 to 20 minutes at 350°F.
  9. Serve with meat, or as a main course with salad.