1) Allow cream cheese and margaine to reach room temperature.
2) While slice orange in half, peel one half of orange and grate rind using a small shredder set aside gratings and remaining half of orange
3) Mix cream cheese and butter until well blended.
4) Add vanilla extract and pineapple juice to mixture.
5) Slowly add confectioners sugar until desired consistency is reached (for a fimer frosting add more sugar ).
6) Mix into frosting 1 1/2 teaspoons of orange gratings set remainder aside.
7) If you choose to add food coloring this can be done at this point start with 1 /2 teaspoon of coloring (Hint: you made need to add more sugar if to much food coloring is used to keep desired consistency)
If you are using the frosting for a cake some decorating options are as follows: Slice rings of the orange with the remaining half, remove orange and garnish cake with half moon rind rings and/or take remainder of gratings and sprinkle on the cake (also nice sprinkled on cupcakes)
This recipe also work well with lemon, lime or a combination of your favorite citrus fruits for a fresh citrus based frosting with all natural flavors. If using lemon or lime monitor taste as you are adding to the frosting.
I used this recipe (Orange) with a three layor carrot cake (with raisins, pineapple, walnuts and carrots) and it was awesome.