Preheat oven to 350 F
In a medium bowl, whisk together the flour, baking powder, and salt; set aside.
In a separate large bowl, using an electric mixer on medium speed, cream together butter and sugar until light and fluffy. Beat in egg and vanilla extract; mix well.
Slowly add in the flour mixture to butter mixture, 1 cup at a time, mixing after each addition.
Divide dough in half and pat to flatten into 2 disks. Wrap in plastic wrap and freeze until firm, at least 20 minutes. (Or place in fridge overnight)
Line baking sheet with parchment paper. Remove one disk from freezer (or fridge), then second when ready.
Dust a work surface with some excess confectioner’s sugar for surface prep.
Using a rolling pin, roll out dough to ¼ inch think. (Flatten dough directly on top of confectioner’s sugar)
Use cookie cutters to stamp out desired shapes. (Sprinkle some excess flour on work surface, dip cutter in flour before each cut)
Using a metal spatula or your hands, carefully transfer to prepared baking sheets and chill in the fridge for 10 minutes. Repeat until all scraps of dough are used up.
Bake cookies (either directly on parchment paper, or carefully remove chilled cookies and place on a second ungreased baking sheet). 8 to 11 minutes for large cookies and 6 to 9 minutes for small cookies. Rotating baking sheet halfway through, cook until cookies are slightly golden.
Note: some of the smaller cookies will bake faster than the larger ones. You can remove them from the baking sheet onto the cooling rack, and put the baking tray back in the oven for another few minutes if the larger ones are not done yet.
Remove cookies from baking sheet, let cool completely on wire racks before decorating.
Royal Icing Instruction
In a medium bowl, whisk together the confectioner’s sugar and meringue powder. Add vanilla extract.
Slowly add 3 tablespoons of lukewarm water, 1 tablespoon at a time. The icing will start out thick and lumpy. Slowly add each tablespoon of water (you may not need all of it) until the icing resembles thick honey. Continue to whisk for 2 to 4 minutes until thick and fluffy.
Using a rubber spatula, fill the piping bag with royal icing. To fill the bag, fold over the top to form a cuff, scoop in icing, then unfold and twist to push icing down, releasing any air bubbles. Twist and seal the top of the bag.
When you’re ready to pipe, cut a tiny corner off the piping bag. This will be about ¼ inch from the tip. (Start very small with a test)
Decorate your cookies! Use pipe icing to design patterns with royal icing. Let dry for a minimum of 2 hours. (If icing is applied very thick, it will take longer to dry)