Cream butter in a large mixing bowl; gradually add sugar, beating until light and fluffy. Add eggs and vanilla; mix well. Combine flour and salt; add to creamed mixture, mixing well.
Divide dough in half; set one half aside. Add orange rind and orange food coloring to half of dough, mixing until well blended. Divide orange dough in half; wrap in waxed paper, and chill.
Divide remaining dough in half. Add lemon rind and yellow food coloring to one half, mixing well; wrap in waxed paper, and chill. Add lime rind and green food coloring to remaining dough, mixing well; wrap in waxed paper, and chill.
Shape each chilled portion of dough into two long rolls, 1 inch in diameter; wrap each roll in waxed paper, and chill an additional 30 minutes.
Place two orange rolls, one lemon roll, and one lime roll together lengthwise, alternating colors. Press rolls together firmly to form 1 roll; wrap in waxed paper, and chill. Repeat procedure with remaining dough.
Cut into 1/4-inch slices, and place 2 inches apart on greased cookie sheets. Sprinkle with tinted sugar, if desired. Bake at 350° for 8 minutes. Remove from cookie sheets, and cool completely on wire racks.
Oxmoor House Homestyle Recipes