Preheat oven to 220 degrees C (425 degrees F). Cut pumpkin into chunks and place on a lined baking tray with the onion Add the remaining ingredients and toss to coat. Spread out in a single layer and roast for 25 minutes or until cooked through. Cooking time will vary depending on the size of your pumpkin chunks. Once cooked remove and set aside.
Wash the quinoa and add to a small saucepan with 3/4 cup of water. Cover and bring to the boil. Once boiling turn the heat to as low as possible and allow to cook for 10 minutes. Once cooked fluff with a fork and add to a large bowl. Set aside and allow to cool slightly.
Finely chop the mint and coriander add to the quinoa along with the olive oil, lemon juice, sumac and salt and pepper. Add the pumpkin and toss gently. Add to a serving plate.
Garnish with pepitas, pomegranates and hazelnuts. Serve.
To dry roast the pepitas and hazelnuts. Add separately to a frying and cook over medium heat until golden. Add the hazelnuts to a tea towel and rub with your hands to remove most of the skins. Then roughly chop.