Beat cream cheese and butter at medium speed with an electric mixer until creamy. Gradually add flour, beating at low speed just until blended. Wrap dough in wax paper, and chill at least 2 hours.
Divide dough in half. Divide each half of dough into 24 balls. Flatten each ball with palm of your hand, and place in lightly greased miniature (1 3/4") muffin pans, shaping each into a shell. Cover and chill until ready to fill and bake.