Put decorations in spice jars with shaker lids or in small bowls. Tuck them away until the kids are done with the cookie-cutting.
Put out lots of small, food-safe paintbrushes. You will need a few per color of icing so that no one has to wait for the red while Erin paints Santa’s big belly.
Designate counter space to re-roll scraps; get older kids to help or a patient, speedy, adult.
Make royal icing about two hours before the party. Divide the icing into small, sealable plastic containers. Dye with food coloring or paste, making two of each color you will offer. Make sure you have plenty of white icing too. Cover with plastic wrap down to the surface; you don’t want the icing to set. Chill.
Heat the oven to cookie-baking temperature.
Transfer each sheet of dough to a sheet of the pre-cut parchment. (The waxed paper will be wet and tear easily.) Place one in front of each child; let them go to town with cutters. Have parents help the younger ones. (This is fun for the adults too.) Write each kid’s name in pencil on the parchment paper.
Slide the parchment onto cookie sheets; bake, in batches. Put platters of the pre-baked cookies on the table for kids to decorate.
After cookies that the kids cut out are baked, the kids decorate those.
Don’t worry about the mess. Icing will be everywhere, caked on brushes, smeared on the shaker jars. Sprinkles too. It all cleans up easily.
Keep an eye on the oven or designate someone to do so. You’ll be busy. Kids don’t understand that mistakes happen. They just know you burned their cookies.