Put 4 tablespoons butter in a large saucepan over medium heat. When it melts, add spinach, one handful at a time, stirring, and sauté until it wilts, about 5 minutes. Form 4 nests in the spinach and crack an egg in each. Cover and cook until egg whites are set, about 4 minutes. Garnish: Shaved Parmesan.
Chop 1 white onion and sauté it in the melted butter; add 3 tablespoons white wine. Cook spinach in this as above, and substitute 1 pound mussels for the eggs; cook until they open. Garnish: Fresh parsley.
With Soy and Ginger
Skip the butter. Put 2 tablespoons sesame oil in a large saucepan, along with 2 cloves minced garlic, 1 tablespoon freshly grated ginger and 1 tablespoon soy sauce. Add spinach and braise until completely wilted and soft, about 10 minutes.