For the sugar cookies:

1. In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
2. In a bowl of a stand mixer with a paddle attachment, beat the butter and sugar for 1-2 minutes.
3. Next, beat in the egg and vanilla.
4. Scrape down the bowl and add in the dry ingredients. Mix until just combined. Do not over mix!
5. Shape the dough into a flat disk and refrigerate for at least one hour or up to overnight.
6. When ready to bake the cookies, preheat the oven to 350 degrees F (180 degrees C) and line a couple baking sheets with parchment paper.
7. On a lightly floured surface (or between two floured pieces of parchment paper), roll out 1/3 of the cookie dough to about 1/4" thick. Keep the rest of the cookie dough in the fridge. Cut out as many snowflakes as you can with a cookie cutter.
8. Shape the remaining cookie dough into a disk and refrigerate for a few minutes if has become too warm.
9. Re-roll and continue cutting out until all dough is used up.
10. Place cookie dough on the prepared baking sheets about an inch apart and freeze for at least 15 minutes.
11. Bake the cookies for about 10 minutes until barely golden around the edges. Allow to cool completely before decorating with royal icing.

For the royal icing:

1. In a small bowl, combine the powdered sugar, meringue powder, and water.
2. Using an electric mixer, beat on high speed for about 1-2 minutes until thick.
3. Transfer the icing to a small piping bag and with a very small round piping tip.
4. Decorate cookies as desired.