01 - Melt butter in a large pot over medium heat. Add onion, celery, and carrot. Sauté for 5 minutes until vegetables are softened and fragrant.
02 - Stir in minced garlic and cook for 1 minute until fragrant, being careful not to burn it.
03 - Add diced potatoes to the pot and pour in vegetable broth. Bring mixture to a boil, then reduce heat to low, cover, and simmer for 20 minutes until potatoes are very tender and easily pierced with a fork.
04 - Remove pot from heat. Using an immersion blender, puree soup until completely smooth and creamy. Alternatively, transfer soup in batches to a countertop blender and blend until smooth, then return to pot.
05 - Stir in heavy cream and chopped chives. Season with salt, pepper, and nutmeg. Warm through over low heat for 2-3 minutes, stirring occasionally. Do not allow soup to boil after adding cream.
06 - Ladle hot soup into serving bowls. Garnish generously with additional fresh chopped chives before serving.