1. Melt butter in Dutch oven over medium heat. When foaming subsides, add leeks and cook until soft (do not brown), 5 to 8 minutes. Stir in minced garlic and cook until fragrant, about 1 minute. Add garlic heads, broth, bay leaves, and 3/4 teaspoon salt; partially cover pot and bring to simmer over medium-high heat. Reduce heat and simmer until garlic is very tender when pierced with tip of knife, 30 to 40 minutes. Add potatoes and continue to simmer, partially covered, until potatoes are tender, 15 to 20 minutes.

2. Discard bay leaves. Remove garlic heads; using tongs or paper towels, squeeze garlic heads at root end until cloves slip out of their skins. Using fork, mash garlic to smooth paste in bowl.

3. Stir cream, thyme, and half of mashed garlic into soup; heat soup until hot, about 2 minutes. Taste soup; add remaining garlic paste if desired. Using immersion blender, process soup until creamy, with some potato chunks remaining. Alternatively, transfer 1 1/2 cups potatoes and 1 cup broth to blender or food processor and process until smooth. (Process more potatoes for thicker consistency.) Return purée to pot and stir to combine, adjusting consistency with more broth if necessary. Season with salt and pepper and serve, sprinkling each portion with chives and garlic chips. For Garlic Chips Heat oil and garlic in 10-inch skillet over medium-high heat. Cook, turning frequently, until light golden brown, about 3 minutes. Using slotted spoon, transfer garlic to plate lined with paper towels; discard oil. Sprinkle lightly with salt.

Serves 6 As a Main Course