Heat a nonstick frying pan over a medium-low heat and dry-fry the pumpkin seeds for 2–3 minutes, stirring frequently, until slightly golden and toasted.

Set aside.

Place the squash in a roasting tin, drizzle with 1 tablespoon of the oil, and sprinkle with the chili flakes and cumin seeds.

Roast in a preheated oven, 200°C (400°F), Gas Mark 6, for 30–35 minutes until tender, tossing occasionally.

Heat the remaining oil in a saucepan, add the onion and garlic, and fry for 3–4 minutes.

Add the squash and stock and simmer for 5 minutes.

Using a hand-held blender, blend the soup until smooth, adding more liquid to loosen, if necessary.

Ladle the soup into 4 bowls and serve topped with dollops of the yogurt and the toasted pumpkin seeds.