1. Preheat oven to 400°. Beat first 4 ingredients at medium-high speed with an electric mixer 5 minutes or until thick and pale. Add butter and food coloring, beating until blended.
2. Sift together cake flour and next 3 ingredients; fold into egg mixture. Spoon batter into 2 lightly greased shiny madeleine pans, filling three-fourths full (about 1 Tbsp. per madeleine).
3. Bake at 400° for 8 to 10 minutes or until centers of madeleines spring back when lightly touched. Immediately remove from pans to wire racks, and cool completely (about 20 minutes). Dust with powdered sugar just before serving, if desired.