16ouncesunsalted butter454g, room temperature, cut into 1-inch pieces
1tsppure vanilla extract optional4.9mL
¼tspcream of tartar0.84g
⅓cupwater79mL
Instructions
Beat the egg whites, salt and cream of tartar, slowly add in ⅓ cup of sugar and continue beating until soft peaks form.
While the eggs are getting whipped, add the remaining sugar and 1/3 cup water into a medium pot and place on medium-low heat.
Stir until sugar melts and becomes clear.
Maintain at medium-high heat until temperature reads 235-240*F.
While the mixer is going on medium, drizzle the sugar syrup into the bowl down the side, avoiding the whisk attachment in a slow, steady, thin stream. At this point the meringue should be at the soft peak stage.
Continue to run mixer until meringue is cool/tepid.
Switch to a paddle attachment. Add room temperature butter into running mixer one tablespoon piece at a time.
Add the salt and vanilla if using.
It is common for the buttercream to start looking broken during this time. You might think it is ruined, but trust in the process. Keep adding the butter a little at a time and keep whipping. It will come back together into a silky smooth buttercream.
Notes
Italian Meringue icing is made the EXACT same way (you just don't add the butter).
Although the term, Meringue, actually first appeared in a French cookbook written by François Massialot in 1692, interestingly there was an earlier recorded English manuscript book in 1604 by Lady Elinor Fettiplace, who gave a recipe that can be easily recognizable as a Swiss meringue cookie. She called this recipe “white biskit bread.”
FLAVOR OPTIONS
Vanilla Italian Meringue Buttercream: Add in 2 tsp vanilla extract at the end
Chocolate Italian Meringue Buttercream: Melt 4 oz of bittersweet chocolate and allow to cool slightly. Fold it into the prepared buttercream.
“Wedding Cake” Italian Meringue Buttercream: Add 1 tsp vanilla extract and 1/4 tsp almond extract
Lemon Curd Italian Meringue Buttercream: Fold in 1 cup of lemoncurd to the prepared buttercream
Strawberry, Raspberry, or Blackberry Italian Meringue Buttercream: Fold in 1 cup of seedless preserves