Place coriander seeds in wok without any oil over low heat. Continuously stir for 5 minutes. Crushed roasted coriander using mortar and pestle. Keep aside until required.
Heat butter in a non-stick pot over low heat.
Add onion, leek and ginger. Stir-fry for 2 minutes, stirring regularly.
Add pumpkin and chicken stock. Let it simmer for 12 minutes or until pumpkin is soft.
Add milk and simmer for 10 minutes. Stir regularly.
Add salt according to your taste.
Remove from heat and scoop into soup bowl.
Sprinkle roasted coriander powder and serve