Measure the Knox Gelatin in a bowl then add the cold water. Stir. Boil some water and add the boiled water to the cold mixture. Stir. Allow to fully dissolved 5-10 minutes. Take the zest of the lemons and limes and juice them as well. I did this all in the same container. Soften the margarine in a microwave safe bowl. Add the shortening and Perfect Sugar Cookie Mix. Add the Gelatin and Citrus Juice mixtures to the main bowl and mix until the dough is formed. If the dough is too sticky, add a little more perfect sugar cookie mix. Dough should easily form dough balls without sticking to your hands.
Preheat oven to 350 degrees. Grease cookie sheets. Take teaspoon size dough balls and place on cookie sheets. I arranged it so I had 30 per sheet. Bake for 12 minutes and then allow to cool another 6 minutes on the cookie sheets. Finish cooling on wire rack. Cookies will flatten but still be a nice thickness. They will be firm, on the bottom, but soft on top. They won't look very golden, still mostly white on top.
Frosting: Mix until smooth and creamy and a good consistency for making sandwich cookies. I put the frosting in a plastic bag and piped the frosting onto one half of the cookie to make this process go quickly. This recipe yields around 50 sandwich cookies that are approximately 1 1/2'' in diameter.