Preheat oven to 375 degrees F. With a pastry brush, butter the madeleine molds well with some of the clarified butter.
In a food processor, grind the almonds with the sugar to a very fine texture. In a large bowl with an electric mixer cream the butter, add the almond mixture, beating, and beat the mixture until it is light and fluffy. Add the eggs, 1 at a time, beating well after each addition, and then beat in the rind. Into a bowl sift together the flour, baking powder and the salt and add to the butter mixture, alternately with the lemon juice, beginning and ending with the flour mixture and blending the batter after each addition. Using an offset spatula, spread the batter into the buttered madeleine molds, scraping off any excess batter with the edge of the spatula. Place the filled molds on a baking sheet. Bake the madeleines in the lower third of the oven for 10 minutes, or until golden at the edges. Turn them out onto a rack to cool. Wash and dry the molds, butter again and repeat process with remaining batter.
Sift the confectioners' sugar over the cooled madeleines prior to serving.
Recipe courtesy of Gourmet Magazine