Combine white sugar, salt, margarine, vanilla, and eggs in a bowl.

Beat the ingredients well using an electric mixer until fully combined.

Gradually add the flour to the mixture.

Mix gently with a spoon until the flour is well blended into the wet ingredients.

Cover the dough and place it in the refrigerator.

Chill the dough thoroughly for at least 30 minutes.

Roll the chilled dough out on a flat, floured surface to a 1/4 inch thickness.

Cut out desired cookie shapes and place them on an ungreased cookie sheet.

Bake in a preheated oven at 350 degrees for 12-14 minutes, until the bottoms are slightly brown.

Do not overbake the cookies.

Let the cookies cool completely on wax paper in a single layer.

Prepare the frosting: Combine powdered sugar, softened margarine, and vanilla in a bowl.

Add a splash of milk to moisten the powdered sugar. Gradually add more milk to achieve the desired frosting consistency.

Add food coloring to the frosting, if desired.

Once the cookies are cooled, frost and decorate with colored sugars or other desired decorations.