Mix carrot, onion, garlic and coriander seeds with olive oil in a bowl.
Layer the mixed vegetables on a baking tray or in a pan.
If you're roasting it in the oven then preheat the oven to 180ºC. Roast the vegetables for 20-30 minutes or till the carrots are done.
If you're roasting in a pan, then roast over medium heat for 10- 15 minutes, stirring the vegetables occasionally.
Puree the vegetables with the water or stock and fresh ginger.
Pour the pureed mixture into a pan.
Add salt, pepper, coriander and nutmeg powders.
Heat the soup over medium heat. Do not let it boil. Let it simmer gently over low heat till it is hot.
Add lemon juice, sour cream or yogurt and coriander and serve it hot.