Place shortening and corn syrup in mixing bowl, fitted with the paddle attachment and beat until creamy.
Add flavorings and salt then, beat until blended.
Mix in powdered sugar all at one time, switch to your dough hook attachment.
Blend thoroughly, allowing the mixture to knead with the dough hook for approximately 5 to 7 minutes . The mixture will be very stiff.
turn icing onto work surface and knead for a few more minutes until smooth and well blended.
Store icing in sealed plastic bag then place bag in airtight container. Icing can be refrigerated for several weeks or frozen for several months.
Let come to room temperature before using,
For chocolate version: add 1/2 cup sifted cocoa powder, and decrease the powdered sugar to 6-1/2 to 7-1/2 cups.This will have a luscious Tootsie-Roll taste.
This will cover a two layer 10-inch round cake that has been torted and filled or just the two cake layers with a single layer of filling.