This is the buttercream icing they taught in the Wilton's class at Michael's I took. I'm assuming it's dairy free :)
1 stick crisco
2 tbsp. water
1 tsp. flavoring (butter, almond, or vanilla extracts in any combination you want)
1 tbsp. meringue powder (this can be left out if it has any dairy in it. I've done that before by accident and it didn't affect the taste at all)
4 lbs. powdered sugar.
This makes a stiff consistency which is good for flowers. Add 1 tbsp. of water for a medium consistency for most decorating needs and another tbsp. of water for a thinner consistency which is best for frosting the cake.
It's very easy to decorate with and tastes pretty good if you like buttercream.