Step 1

Melt the butter in a large pot or Dutch oven over medium heat. Add the onion and garlic and cook until soft, 4 to 5 minutes; do not brown. Add the broccoli stems, broth, water, salt, and pepper. Bring to a boil and cook over medium-high heat until the stems are partially cooked, about 10 minutes. Stir in the broccoli florets, cream, and nutmeg, and continue cooking until the florets are tender, about 5 minutes.

Step 2

Using a hand-held immersion blender, purée the soup until completely smooth. (Alternatively, cool the soup slightly and use a blender to purée in batches. Be sure to remove the center knob on the blender and cover with a dishtowel to avoid splatters.) Add 1-1/2 cups of the cheese and stir until melted. Taste and adjust seasoning with salt and pepper. Ladle the soup into bowls and sprinkle with the remaining cheese.

Step 3

Note: The garlic need only be smashed and peeled, rather than minced, as leaving it in large pieces prevents it from burning, and it all gets puréed in the end anyway. To smash and peel a clove of garlic, place the unpeeled clove on a cutting board. Take a chef's knife and place the blade flat on the clove (sharp side facing away from you). Use the heel of your hand to press the blade down on the clove. The garlic should be smashed and the peel should slip right off. It is not necessary to chop the garlic further.

Step 4

Make-Ahead Instructions: The soup can be made ahead and refrigerated for up to 3 days. Reheat gently over medium heat until hot.

Step 5

Freezer-Friendly Instructions: Although soups made with dairy products are more likely to have flavor and texture changes when frozen, this soup freezes well. For best results, allow the soup to cool completely, then pour into plastic containers, leaving an inch or two of space at the top to give the soup room to expand as it freezes. Seal the containers and freeze for up to 2 months. When ready to serve, thaw the soup overnight in the refrigerator and reheat in a saucepan over medium-low heat, stirring frequently, until warmed through.