The key to stenciling on buttercream is to make sure that your surface has crusted over and is not sticky. Otherwise, the stencil will lift off your base icing. You can pop your cake in the freezer or refrigerator or follow this recipe:
Carol’s Crusting Buttercream Frosting Recipe
Makes enough for one 2-layer 9-inch cake or 2 dozen cupcakes*
• 1 cup (2 sticks) unsalted butter, softened
• 6 to 8 cups confectioners’ sugar
• 1/3 -1/2 cup heavy whipping cream or milk
• 2-4 teaspoons vanilla extract (depending on taste preference)
Place softened butter in a mixing bowl. Add 4 cups of sugar and then add 1/3 cup cream and 2 teaspoons of vanilla. On the medium speed of an electric mixer, beat until smooth and creamy, about 3-5 minutes. Gradually add the remaining sugar, 1 cup at a time, beating well after each addition (about 2 minutes), until the icing is thick enough to be of good spreading consistency. (You may not need to add all of the sugar). Use additional cream or sugar, if necessary, to achieve the right consistency. If desired, add 1-2 more teaspoons of vanilla for taste.
Use and store the icing in an air tight container, for up to 3 days, at room temperature. Icing will set hard if chilled.
To use with a stencil:
• Ice cake and chill in refrigerator if surface is sticky (30 min - 1 hour). If you can touch the icing and it doesn’t come off on your finger – then it’s ready for a stencil.
• Thin left over frosting with a bit of cream so it is smooth and creamy. Place stencil on cake surface and spread icing over it. Lift stencil.
• If the base icing gets too soft, return cake to refrigerator to crust over again before continuing.
• If sprinkling with colored sugars, rub Crisco on top of your stencil first to help keep the sugars from falling through the stencil openings when you lift the plastic