"Madeleines are plump, little sponge cakes traditionally flavored with just vanilla. These have a small bit of orange zest in them for added warmth and aroma. Cook’s note: The trick to getting notoriously stubborn madeleines out of the pan without cracking them is to very generously grease the pan. Butter works best for this recipe, and it gives the added benefit of helping the madeleines achieve their trademark golden color...."