Courtesy of Karen's Cookies, but modified by Kay and further modifications by me to suit UK ingredients.
Again, any cup/spoon measures are American.
Meringue Powder Buttercream Icing
* 1/2 cup 1/3 cup water
* 5 individual packages of Dr Oketer egg white powder, about 30g 3 T. meringue powder
* 4 tbsp ½ cup shortening (really recommend Crisco!)
* 1kg 4 ½ cups powdered sugar (1 lb. 3 oz. If you have a scale)
* 1 tsp. vanilla extract (use clear vanilla if you want a pure white icing)
* ¼ tsp. almond extract
Place half of the powdered sugar and the meringue powder in the bowl of an electric mixer. Whisk together well. Turn on mixer (use whip attachment) and, while motor is running, slowly stream in the water. Mix until everything is incorporated. Turn mixer to high speed and whip until stiff peaks form. Add flavorings and mix well. Change to paddle attachment (for stand mixer) or dough hook (for Bosch). If using a hand mixer, use the same beaters you were using before. Add remaining powdered sugar and shortening and whip for 2-3 minutes more.
Note: Don't skimp on the whipping time after adding the shortening. You really need to whip it well to prevent separation later.
You will need to add more water to suit the application (flooding v detail). I use the 5-6 second rule to flood (slide knife through surface and should flatten totally within 5-6 seconds). And 10 seconds or more for detail. Icing is very much trial and error to learn what is right for your application.
I use the whisk in both steps. I also like to make the icing the day before because colours will darken and air bubbles are less likely.