I haven't found the perfect recipe yet so I Googled the heck out of madeleines and found that nifty old Cook's Illustrated did a piece on it in March 1996. Oh, the excitement when you read the teaser description: "...and discover how to keep them from sticking to the pan!" My library didn't have it so I asked another library system to fax me The Secret. Nothing like using Librarian Powers for French cookie goodness!
I made the original madeleine recipe. The crumb was better than others - it uses 1/4 c flour and 1/4 c cake flour and NO leavening agent (all the others had baking powder). 2 yolks and 1 whole egg mixed for 3 minutes, and then 1/4 c sugar and vanilla beat for another 3 minutes seem to give the madeleines a lift. 4 T of melted butter is added at the end - that is much like the other recipes. I didn't get a hump...but that's okay. I think the flavor was a bit bland...I would add some lemon zest next time. I used the Madagascar Bourbon Pure Vanilla Bean Paste to give 'em some little freckles.
Another tip is to turn them onto a clean kitchen towel instead of a cookie rack so they don't get those ugly lines. Great idea!
The main secret is to grease the molds with a mixture of two teaspoons melted butter and one teaspoon all-purpose flour. This sorta worked for me.
I also tried to make the chocolate madeleines but they turned out very tough. I'll stick to the classic recipe for now.