01 - Melt butter in a large pot over medium heat. Add onion, celery, and carrot. Sauté for 5 minutes until softened and fragrant.
02 - Stir in minced garlic and cook for 1 minute until aromatic, being careful not to burn.
03 - Add diced potatoes and vegetable broth to the pot. Bring to a boil, then reduce heat to low, cover, and simmer for 20 minutes until potatoes are completely tender when pierced with a fork.
04 - Remove from heat. Using an immersion blender, puree the soup until completely smooth and velvety. Alternatively, transfer in batches to a countertop blender and return to the pot.
05 - Stir in heavy cream and chopped chives. Season with salt, pepper, and nutmeg if using. Warm through over low heat for 2-3 minutes, but do not allow to boil.
06 - Ladle hot soup into serving bowls and garnish with additional fresh chives. Serve immediately while hot.