Powdered Sugar -2.25 lbs , one packet
Meringue powder- 5 T
Cream of tartar - 1 t
Water- 3/4 C

Mix the warm water and meringue powder for 30 seconds and then add cream of Tatar , optional, and whisk for a minute or 2 until smooth.
Add the powdered sugar in batches so that it doesn’t spray all over and mix well. Then at a low speed and with a paddle attachment if using the stand mixer, let is mix for about 10 minutes.
It is right if the icing separates when make a line with a knife or spoon and comes back together in 10-15 seconds .
Keep it tightly covered at all times.