Combine all ingredients in a stand mixer with whisk attachment.
Beat on medium (maybe a 6) for 7 minutes. Gradually add more water as needed to get to the right consistency and scrape down the sides at least once.
Divide into bowls so you can add in food coloring. I prefer using my glass 4 cup measure because after I prep my stiffer, border icing, I can pour the thinner flood icing into bottles.
Going from here, you have choices. You can use piping bags or bottles. I use both. I put my border frosting into piping bags and the flood icing in bottles. I put the bottles face down in glasses so that gravity helps me out and I don’t have to shake the frosting down as I work. Get work station prepared and have fun.