Creamy Cauliflower Soup with Brown Butter

INGREDIENTS

head (approx. 2 pounds) cauliflower

7 tbsp

unsalted butter, divided

leek, white and light green parts only, halved and thinly sliced

small onion, halved and thinly sliced

salt & pepper

4 1/2 cups

water

1/2 tsp

white wine or sherry vinegar

3 tbsp

fresh chives, snipped