My Favorite Icing

I got this recipe from a Dentist, Martha Shepartycky, I used to see when I lived in Churchill!
This is my very favorite icing. It is not overly sweet and has quite a unique texture.
It is fussy to make and takes time but it is worth it. Do not shorten beating times prescribed.
 It freezes well so I will make 1/2 or full recipe leave it white and then when ready to use thaw and color it with food coloring.

2 cups granulated sugar
6 Tbsp. cornstarch
2 1/2 cups milk
2 cups Crisco shortening (do not substitute)
1 cup butter
4 cups icing sugar
4 tsp. vanilla
2 Tbsp. room temp. milk

Whiz granulated sugar together with cornstarch in a blender jar. While blender is running add milk and whiz till mixture is smooth. Pour into a large saucepan and cook over low heat, stirring constantly, until mixture reaches a boil and then let boil 2-3 minutes. Remove from heat and cover saucepan with wax paper to prevent skin from forming on surface and refridgerate until well cooled.
While mixture is coolingbeat butter till fluffy. Gradually add icing sugar,vanilla and room temp. milk. Beat until light and fluffy. Set aside.
In a large bowl, beat shortening at high speed of electrical mixer for at least 3 minutes. Add the sugar/cornstarch mixture and beat at high speed for 6-9 minutes. At low speed add prepared butter icing gradually and when all combined beat at high for 4-5 minutes. Add food coloring as desired.
Yield : enough to frost and decorate 4 -  9x13 cakes and still have enough for a tate or two.
           It is not recommended for petalled flowers but is perfect for drop flowers, borders and writing.