Ingredients

• 3 tablespoons butter
• 4 cups sliced celery (about 8 stalks)
• 1 1/2 cups chopped leeks (white and pale green parts only; from 2 medium)
• 3/4 pound Yukon Gold potatoes, peeled, diced
• 4 cups (or more) low-salt chicken broth
• 1/3 cup plus additional crème fraîche
• 1/4 teaspoon cayenne pepper
• Chopped fresh parsley (optional)
• Stilton Toasts

Instructions

1. Melt butter in heavy large pot over medium-high heat. Add celery and leeks. Sauté until celery is slightly softened, about 4 minutes. Add potatoes and 4 cups broth. Bring to boil. Reduce heat to medium-low. Simmer, uncovered, until all vegetables are tender, about 30 minutes. Working in batches, puree soup in blender until smooth. Return to same pot. Whisk in 1/3 cup crème fraîche and cayenne pepper. Season soup to taste with salt and pepper. (Can be prepared 2 days ahead. Cool, then cover and refrigerate. Rewarm over medium heat before serving, adding more broth to thin if desired.)
2. Ladle soup into bowls. Swirl 1 to 2 teaspoons additional crème fraîche into each. Sprinkle with parsley, if desired. Serve with Stilton Toasts.