Instructions:

• Place room temperature egg whites and cream of tartar in stand mixer bowl with the whip attachment. Set aside.
• Put the granulated sugar in a small saucepan and add the water. Do not mix it. Cover the pan and place it over high heat. When the sugar begins to boil, uncover it and clip your candy thermometer to the side of the pan making sure the tip of the thermometer is directly in the boiling sugar. Once the sugar reaches 230°, start mixing the egg whites on high. By the time the sugar reaches 240°, the egg whites will have formed stiff peaks.
• When the sugar reaches 240° pour the boiling sugar (at a medium pace) into the stiff egg whites with the mixer still on high. Leave the mixer on high until the egg whites have returned to room temperature. When you touch the outside of the mixing bowl it should not be warm at all.
• Leaving the mixer on high speed, add the room temperature butter half of a stick at a time. Once all the butter is incorporated let the mixer whip the buttercream for 30 - 60 Seconds.
• Turn the mixer to a low speed and add the vanilla.