In a large mixing bowl, combine the softened butter and vegetable shortening. Using an electric mixer, beat on medium speed until the mixture is light and fluffy, about 2-3 minutes.
Add the salt, vanilla extract, butter flavoring, and almond extract to the mixture. Continue to beat on medium speed until well incorporated.
Sprinkle in the meringue powder and mix until fully combined.
Gradually add the sifted confectioners’ sugar, one cup at a time, mixing on low speed to avoid a sugar cloud. Once all the sugar is added, increase the speed to medium and beat until smooth and creamy.
If the icing is too thick, add the tablespoon of milk one teaspoon at a time until you reach the desired consistency. Beat for an additional minute.
Give the icing a final whip on high speed for about 1-2 minutes to enhance fluffiness.
