In medium bowl, stir together flour, baking powder and salt. Set aside.

In large bowl with mixer, cream butter and sugar together until creamy.  Add in eggs and vanilla and mix until slushy.  Gradually add flour mixture to butter mixture and blend just until combined into a soft dough.  Divide dough in two and cover each with plastic wrap.  Shape into a round flat disc about 5" wide and refrigerate until firm - at least an hour and up to three days. Keep dough refrigerated until you are ready to roll it out.

Place about a 1/4 cup flour and 2 T of sugar onto a flat surface and swirl together. Wipe flour on rolling pin also. Place one disc of dough in center and begin to roll out the dough to 3/16" to 1/4" thick, turning the dough in the flour, so it does not stick to the surface. Use cookie cutters to make cookie shapes and place slightly apart on ungreased baking sheets.

Bake in a 400° oven for 8 to 10 minutes or until edges begin to brown.  Transfer to wire racks to let cool completely before decorating.

While cookies are cooling, make buttercream icing.  In large bowl, cream shortening and butter with electric mixer.  Add vanilla.  Gradually add sugar, one cup at a time, beating well on medium speed.  Scrape sides and bottom of bowl often.  When all sugar has been mixed in, icing will appear dry.  Add milk and beat at medium speed until light and fluffy.  Add more powdered sugar, 1/4 cup at a time if it seems too thin or oily.

Divide icing into separate bowls to add and mix in food coloring.  Fold back opening of a plastic decorating bag with round tip or heavy duty ziploc bag. Using a rubber spatula, scrape contents of each bowl and fill the bag with icing near the opening or corner of ziploc bag.  Snip off corner of the ziploc bag to create an opening.  When piping icing onto cookies, push icing from the top of the bag with the palm of right hand as the left hand guides the tip. Do not push or add pressure near the opening.