SWISS MERINGUE BUTTERCREAM
3 sticks unsalted butter (12oz. 339g) AT ROOM TEMPERATURE
5 egg whites ( 3/4 cup, 168g)
1/2 tsp (2g, 1/8oz) cream of tartar
1 cup ( 205 g) granulated sugar
2 TBSP (21g) vanilla extract
Place the egg whites, cream of tartar, and sugar in a heat proof bowl (I use my kitchen aid mixing bowl). Put this over a pot of simmering water, whisking by hand until a candy thermometer attached to the side of the bowl registers 140 degrees.
Transfer this to your mixer and put in the whisk attachment. Whip on medium high speed until it reaches stiff peak stage This could take about 10 min. The bottom of the bowl will cool off . The mixture will become fluffy and glossy.
While the meringue is beating, cut the butter into tbsp sized pieces.
When the meringue is ready, put the paddle attachment on the mixer and add the butter a few pieces at a time while beating on low speed.
The mixture may look like it is separating after you add the butter. Don’t worry, just continue beating on medium-high speed and it will become smooth again.
You can use immediately ….refrigerate in an airtight container for 5 days or freeze for 1 month. If frozen, bring to room temp and beat with paddle attachment on low speed until it is smooth again…..3 to 5 minutes