I found this recipe in Martha Stewart's Baking Handbook. Great book!
Melt one stick of unsalted butter and set aside to cool.
Grate enough lemon and orange peel to make about 2 tablespoons. Add this and a 1/4 teaspoon orange or lemon extract to the cooled butter. (If you want to omit this, just add vanilla extract.)
Whip 3 whole eggs plus 1/2 teaspoon salt till frothy.
Grease and flour Madeleine pans and fill moulds about half full. Bake at 350F for 12-14 minutes. Should make 24 Madeleines.
Done! Now, to get to the rest of my Baking Bucket List. What's on yours?