Clean leeks carefully to remove dirt. Slice into thin rings. Leeks are the base for this creamy soup and give a delicate onion flavor.

In a large pot, melt butter over medium heat. Add sliced leeks and cook until soft, about 5–7 minutes. Stir often to prevent burning.

Add peeled and chopped potatoes to the pot. Stir to combine with leeks and butter. This makes the soup hearty and smooth.

Add chicken or vegetable stock. Bring to a boil, then reduce heat. Simmer for 20 minutes until potatoes are very soft and tender.

Use an immersion blender or regular blender. Blend until smooth and creamy. Take care when blending hot liquids to avoid splashing.

Stir in heavy cream slowly. Heat gently but do not boil. This keeps the soup smooth and rich without curdling the cream.

Add salt and black pepper. Taste and adjust seasoning as needed. This ensures the flavors are balanced and perfect.

For classic Vichyssoise, chill in the fridge for at least 2 hours. Serve cold or warm, garnished with chopped chives.