Sarah's Italian Meringue Buttercream
This is sort of a finicky frosting, but so good. Once you master this type of buttercream, you will never go back to the overly sweet powdered sugar type icing. It's light and fluffy and just the right sweetness. It's the type of frosting found in most high-end gourmet pastry shops. You will need a candy thermometer for this recipe. Makes enough to generously frost a two-layer 9-inch round cake.
Recipe Summary test
If syrup looks crystallized in step 2, it is because it was heated too quickly and you will need to start the syrup over. If buttercream looks curdled in step 4, continue to beat until smooth.
Vanilla Bean: Beat in seeds scraped from 1 vanilla bean pod
Chocolate: Beat in 1/2 cup semisweet chocolate that has been melted and cooled
Raspberry or strawberry: Beat in 1/4 to 1/2 cup raspberry or strawberry puree
Other flavors: Add 1 to 2 teaspoons flavor extract