Preparation Melt butter in a large pot over medium-high heat. Working in 4 batches, add spinach to pot, tossing to wilt between batches. Stir in cheese, crème fraîche, and mustard. Using an immersion blender, regular blender, or food processor, pureÌe spinach mixture until very smooth. Season to taste with salt and pepper.
Preparation Melt butter in a large pot over medium-high heat. Working in 4 batches, add spinach to pot, tossing to wilt between batches. Stir in cheese, crème fraîche, and mustard. Using an immersion blender, regular blender, or food processor, pureÌe spinach mixture until very smooth. Season to taste with salt and pepper.