Preheat oven to 375 degrees. Heavily butter madeleine mold including outer edges and chill. In bowl of electric mixer beat eggs with sugar for 6 to 8 minutes or until mixture falls in a ribbon when beater is lifted. Stir in grated orange rind and orange juice. Sift flour over mixture, one-fourth at a time and fold in lightly with a rubber spatula. Add butter in a stream, folding it in and making sure that no butter remains at the bottom of the bowl. Spoon batter into prepared madeleine mold, filling each indentation two-thirds full and arrange mold on baking sheet. Bake in lower third of oven for 10 minutes or until golden brown at the edges. Turn them out onto a rack and let cool to warm.;
TO CLARIFY BUTTER
In a heavy saucepan melt the butter over low heat. Remove the pan from the heat, let the butter stand for 3 minutes, and skim the froth. Strain the butter through a sieve lined with a double thickness of rinsed and squeezed cheesecloth into a bowl, leaving the milky solids in the bottom of the pan. When clarified, butter loses about one fourth of its volume. Pour the clarified butter into a jar or crock and store it, covered, in the refrigerator.