Preheat oven to 350°. In a large bowl, cream first four ingredients until light and fluffy. Mix juice and champagne. Add flour to creamed mixture alternately with juice mixture, beating well after each addition.
Cut a small hole in the tip of a pastry bag or in a corner of a food-safe plastic bag; insert a #1M star tip. Transfer dough to bag; pipe 2-in. circles 2 in. apart onto parchment paper-lined baking sheets.
Bake until edges are set, 10-12 minutes. Cool on pan 5 minutes. Remove to wire racks to cool.