01 -
In a big bowl, toss in powdered sugar, meringue powder, and 9 Tablespoons of water.
02 -
Whisk everything on high speed for about 1.5–2 minutes with an electric mixer. Scoop up the icing with the whisk; it should fall smoothly and spread out within 5-10 seconds.
03 -
If it's too thick, splash in a bit more water (1 Tablespoon at a time). Too runny? Either beat longer to aerate or sprinkle in a bit more sifted sugar.
04 -
Spread the icing thinly onto cookies. Leave it for 2 hours at room temperature to fully harden.