Melt butter in a stock pot over medium heat. Add onion and garlic, season with salt and pepper and cook, until onion and garlic have softened, about 10 minutes.

Add carrots, serrano, sliced ginger, and chicken broth and bring mixture to a boil. Reduce heat to a simmer and cook until carrots are completely tender, 15 to 20 minutes

Remove makrut leaves, and using a blender puree soup until smooth, then pass through a fine mesh chinois. Adjust seasonings if needed, then add lime juice and chopped cilantro.

Combine the crème fraiche, grated ginger, chives, lime zest, and lime juice with a pinch of salt in a small bowl.

Top each serving of soup with a dollop of crème fraiche mixture.