Meringue Powder Buttercream is perfect for making large buttercream flowers. I used an Ateco pastry tip #403 to make the flower petals and a Wilton pastry tip #233 for the yellow center.
In a large bowl, place the sugar, meringue powder and salt. Add boiling water. With an electric mixer, mix on high speed (with the whisk attachment) and beat until stiff peaks form (about 7-8 minutes). Pour into a clean bowl, cover and save for later.
In the same large bowl, add the vegetable shortening. With the mixer on low, gradually add the powdered sugar. Continue to beat the mixture until very creamy (about 3 minutes).
Add the meringue and flavorings to the mixing bowl. Beat for 10 minutes. It should be very light and fluffy. Make sure to keep this frosting covered and do not refrigerate. Store at room temperature in an airtight container. Frosting will last a couple of months. (Note: This icing will form a crust.)