Place the egg whites and sugar in a heat proof bowl. We prefer to use the metal bowl of our stand mixer.

Fill a pot smaller than your bowl with a couple inches of water and bring to a boil. Once boiling turn down to a simmer and set the bowl on the pot to create a double boiler. Continuously stir the egg whites and sugar until the sugar has fully dissolved or the temperature reaches 160 degrees on a candy thermometer.

Transfer the bowl to a stand mixer fitter with the whisk attachment and mix on high until the mixture holds stiff peaks, about 8-10 minutes.

While the meringue is mixing cut the butter into 1 inch cubes.

When the meringue forms stiff peaks continue mixing on high and add the butter one cube at a time. Once all the butter has been added mix in all the vanilla. After the vanilla has been added continue mixing on high for 5 minutes to create your silky smooth buttercream.