To make the madeleines:
In a saucepan heat the butter over medium-high heat. It will bubble, then foam and finally the solids in the butter will brown and smell nutty.
Strain the browned butter into a bowl and allow it to cool. It shouldn't be solid, but no longer hot. Sift together the sugar, flour and almond meal.
Beat the egg whites until foamy, but still very soft, so they run off the beater when it is lifted. Whisk in the dry ingredients. Add the brown butter, honey and vanilla. If you want a lemon-scented cake, then stir in the zest.
Place the batter into a container, cover and chill for at least 2 hours, but this can be done a day or two ahead.
To bake the madeleines:
Preheat the oven to 375 degrees F.
Generously grease the pan with butter. (I highly recommend getting a nonstick madeleine pan).
Fill the pans about 3/4 of the way with the chilled batter. This may require you to wet your finger tips to spread the sticky batter evenly in the pan.
Bake the cakes for about 18 minutes or until they are golden brown on the edges and pale, but firm on the top.
The cakes will dome on the top and that is part of their signature look.
Dust with a little confectioners' sugar and serve warm or allow to cool.