01 - Slice leeks in half lengthwise, rinse thoroughly to remove grit, then slice thinly.
02 - Melt butter in a large pot over medium heat. Add diced onion, sliced leeks, and minced garlic. Sauté for 5 to 7 minutes until softened without browning.
03 - Incorporate diced potatoes, bay leaf, kosher salt, and black pepper. Stir to evenly coat the vegetables with seasonings.
04 - Pour in vegetable stock. Bring to a boil, then reduce heat to low. Cover and simmer for 20 minutes until potatoes are tender.
05 - Discard the bay leaf from the pot before blending.
06 - Use an immersion blender directly in the pot, or blend in batches using a countertop blender until smooth. Return to the pot if using the latter method.
07 - Stir in heavy cream and warm the soup over low heat. Adjust seasoning to taste.
08 - Ladle the soup into bowls and garnish generously with finely chopped fresh chives.