Step 1

Melt butter in heavy large deep skillet over medium-low heat. Add leeks and sauté until tender, about 8 minutes.

Step 2

Combine mussels, wine and parsley sprigs in large Dutch oven. Cover and cook over high heat until mussels open, about 6 minutes. Using tongs, transfer mussels to large bowl, discarding any that do not open. Strain mussel juices into skillet containing leeks. Add saffron and cream to skillet; boil until reduced to sauce consistency, about 2 minutes. Stir in minced parsley. Season with salt and pepper. Add mussels and any accumulated juices to skillet. Stir over medium heat until heated through, about 2 minutes. divide mussels among 4 bowls; pour sauce over.