Cauliflower with Leek "Ash"

Preparation

1. Step 1

   Preheat oven to 500°F. Set vents to high and open a window for adequate ventilation. Place leek on a foil-lined baking sheet. Roast until blackened, dry, and crisp, 70-90 minutes. Let leek cool. Break into shards. DO AHEAD: Leek ash can be made 3 days ahead. Store airtight at room temperature.

   Step 2

   Using a mandoline, thinly slice 3 large cauliflower florets lengthwise (reserve trimmings); set aside.

   Step 3

   Bring milk and 1 cup cauliflower trimmings to a boil in a large saucepan; reduce heat and simmer until cauliflower is tender, 20-25 minutes. Let cool slightly, then transfer cauliflower mixture to a blender or use an immersion blender in the pan and purée until smooth.

   Step 4

   Return cauliflower purée to saucepan, add remaining cauliflower florets, and season with salt. Simmer until florets are just tender, 8-10 minutes. Using a slotted spoon, transfer florets to a medium bowl (rinse off any purée on florets).

   Step 5

   Strain purée into another medium bowl. Divide florets among shallow bowls; spoon purée over. Garnish with reserved cauliflower slices; sprinkle with leek ash.