Heat oil in a Dutch oven over medium-high heat.
Add leek, onion and carrots and saute for 7 minutes, until carrots are fork-tender.
If using the habanero, pierce it a few times with a fork and add to the pot. If using hot pepper flakes, add them now.
Then add ginger and garlic and continue cooking for 1 minute. Lower heat to medium, if necessary.
Stir in wine and let cook for 1 minute.
Add water and sweet potato, bring to a boil.
Partially cover, reduce heat and simmer for 30 minutes.
After 30 minutes, remove soup from heat and stir in orange juice and ground coriander.
Remove Habanero, if used.
Place 1/2 of carrot mixture into a blender or use an immersion blender and process until smooth, approx. 2-4 minutes. (IMPORTANT: If using a blender, it is important to take the middle part of the lid out so that air can circulate as the hot mixture is blending. Cover the opening with a clean dish towel so that soup doesn't splash.)
If using a blender, pour first batch of pureed mixture into a bowl and repeat procedure with remaining carrot mixture. Once all of the mixture is pureed pour soup back in the dutch oven.
Stir in honey and salt.
Cook over medium heat for 5 minutes or until thoroughly heated.
Ladle soup into bowls and garnish with a dollop of yogurt and cilantro sprigs, if desired.