Silky smooth Swiss Meringue Buttercream perfect for cakes, cupcakes, and other tasty desserts!
On the stovetop, place a medium saucepot filled ⅓ of the way with water over medium heat, bring to a simmer to use as a double boiler.
In a stand mixer bowl (or large glass or metal mixing bowl), add egg whites and sugar mix with a whisk to combine.
Lower the heat on the stove to low, then place the mixer bowl over simmering water. Whisk constantly to prevent eggs from overcooking, continue for 3-5 minutes.
Continue to whisk until the mixture has reached 160 °F on your candy thermometer, or until the sugar has dissolved between your fingertips.
Immediately remove from the heat and transfer to the stand mixer with the whisk attachment and add the salt. Begin to mix on medium-high speed to create a light meringue for 10 minutes.
Mix until the meringue is room temperature and has a stiff peak.
Next, lower the mixer speed to low and add the butter a few cubes at a time until all the butter is incorporated into the meringue.
Then whisk on medium speed until the mixture is silky smooth and has doubled in size. It'll look like freshly whipped butter.
With a rubber spatula, add vanilla extract and food coloring and mix by hand until incorporated.
Finally, place the buttercream into the refrigerator for 10-15 minutes to set the buttercream before using it.