Line 2 cookie sheets with parchment paper. In a large bowl, combine cookie mix and cake flour. Add shortening, butter, and egg, stirring with a wooden spoon until dough forms. Divide dough into fourths and place each fourth in a small bowl. Add cherry extract and red food coloring to one of the dough portions; mix until dough has no streaks. (Knead with hands, if necessary.) Repeat with remaining dough portions, using coconut extract and green food coloring for one portion, lemon extract and yellow food coloring for another portion, and almond extract and blue food coloring for last portion. Roll each colored portion into a ball and flatten into a disk. Wrap portions separately with plastic wrap and chill in refrigerator for 30 minutes.
Preheat oven to 350 degrees F. Remove blue dough from refrigerator and roll into a log about 9 inches long. Remove yellow dough from refrigerator and use a rolling pin to roll into a rectangle 9 inches long and wide enough to completely encase the log of blue dough. Wrap yellow dough around blue dough, pressing together to seal seam. Repeat with green dough and wrap around yellow dough. Finish with red dough and wrap around green dough. Chill colored log in refrigerator for 15 minutes.
Cut log into 1⁄2-inch-thick slices. Cut each slice in half and place on prepared cookie sheets, spacing 2 inches apart. Bake in preheated oven for 10 to 12 minutes or just until lightly browned on edges. Cool on cookie sheets for 5 minutes. Transfer to wire racks; let cool. Outline yellow arch with decorating gel and sprinkle sanding sugar over gel.
TIP: To make the Rainbow Slices into cookie lollipops, after slicing colored log and cutting slices in half, gently insert a lollipop stick into the blue portion of the rainbow. Continue as directed. To make the pot of gold, place a large apple chunk in the bottom of gold cupcake liners. Insert the lollipop stick into the chunk of apple, so the lollipop will stand up. Fill the cupcake liners with yellow sanding sugar to cover the apple chunk.