Whisk the egg whites in the bowl of a stand mixer until foamy.
Add half of the powdered sugar and mix with the whisk attachment for 1-2 minutes. Add the remaining sugar and mix for another minute.
One tablespoon at a time, add in the water until the mixture is thin enough for the peaks to settle back into the bowl.
Add the food coloring and mix on high for 1-2 minutes. Adjust the water content if necessary.
Transfer the icing to a piping bag fitted with a size 2 piping tip.