In a large mixing bowl, mix together the shortening, sugar, milk and vanilla using an electric mixer. Mix until smooth. Then stir in eggs. Combine well.
In a separate bowl, combine flour, baking powder and salt. Stir well using a fork.
Gently add in flour to the shortening mixture. Adding a little flour at a time. Mix just until both mixtures are combined.
Divide dough in half. Wrap each dough half in plastic wrap then put the dough balls into the refrigerator to chill for at least an hour.
When dough is ready, preheat oven to 375F degrees. Spray a couple baking sheets with nonstick cooking spray or line with parchment paper.
Spread some flour all over a clean counter.
Working with one dough ball at a time (keep the other one in the fridge), put a little flour on the dough itself. And make sure to rub some flour on your rolling pin too.
Start rolling out dough as evenly as possible. You want the dough to be about ¼-inch thick. If it's too thin then you won't be able to scoop the cookies up without them breaking.
Using your favorite cookie cutters, start cutting out shapes. Try to get your cookie shapes as close together as possible to make the most use of your dough. You can take the leftover dough and roll it out again for a second cutting. Generally, after the second cutting, the dough is not really useable for a third cutting.
Lay out cookies on prepared baking sheet. Spread cookies out about an inch or two apart on the cookie sheet.
Bake for about 6-8 minutes at 375F degrees. Allow cookies to cool completely before icing.
To make the icing:
Combine softened butter, powdered sugar, milk and clear vanilla extract.
Whisk until smooth. If mixture is too thin, just add in a bit more powdered sugar until you get it to the consistency you like. Then add in any food colors you are using. I quadruple this recipe and use four different colors. Gather all your icing, and sprinkles, etc. and have fun.
Allow the icing to setup on the cookies for a couple of hours then you should be able to stack them and store in an airtight container.
Make sure you are using real butter. Not margarine. Margarine has a high oil content and cookies will not set up properly.
Ensure the butter is at room temperature – not melted. I usually put the butter out on the kitchen counter the night before I am going to bake.
Check the expiration date on your baking powder. Most baked goods don’t turn out properly because the rising agent (in this case, baking powder) is no longer good.
Don’t pack the flour when measuring. Just dip the measuring cup into the flour, shake off excess then use the flat side of a butter knife to scoop off the excess off the top. This will ensure that you don’t measure out too much flour which will make cookies dry and dense.