For making roses and decorations that must maintain their shape, you’ll need an icing that maintains its consistency. Since butter softens at room temperature, using all vegetable shortening works best in decorator buttercream icing. Also, not using any ingredients that are quickly perishable means this icing will keep at room temperature.
1 cup solid vegetable shortening
1 pound powdered sugar (make sure it’s proper sugar, not a sugar substitute)
1 tablespoon meringue powder
1 teaspoon vanilla–use clear vanilla if pure white icing is needed
2 tablespoons water
Mix all ingredients with an electric mixer until smooth and creamy, scraping down bowl as needed. An optional pinch of salt can be added to help tone down the sweetness. If using, dissolve the salt in the water so stray grains of it don’t wreak havoc in your icing later. If using a stand mixer, this recipe can be doubled.
This yields about 3 cups of icing stiff enough to pipe roses and figures. Adding 1 teaspoon of water per cup of icing (or a tablespoon to the entire recipe) thins the buttercream enough for piping stars, dots, basketweave, borders such as shells, and smaller flowers with flat petals.
Adding an additional teaspoon of water per cup (2 teaspoons per cup or 2 tablespoons to the entire recipe) thins the icing to where it’s ideal for icing cakes and piping smooth lines.