Beat butter and cream cheese at medium speed with an electric mixer until creamy. Gradually add flour to butter mixture, beating at low speed. Shape mixture into 48 balls; cover and chill 1 hour. Place 1 dough ball into each lightly greased muffin cup in miniature muffin pans, shaping each into a shell. Spoon Lemon Chess Pie Filling evenly into tart shells.
Bake at 350° for 25 minutes or until filling is set. Cool in pans on wire racks 10 minutes. Remove from pans; cool completely on wire racks.