Italian Buttercream Frosting
2 c sugar (375g), divided in 2 parts
2/3 c water (150g)
5 large egg whites (150g)
pinch salt, optional
pinch cream of tartar, optional
2 c butter, cubed (4 sticks or 1 pound), Cool but not cold
2 t vanilla extract
Chocolate Version: 1 1/4 c semi-sweet chocolate, melted but not hot
Measure Everything First. You want to make sure that you have everything measured out and ready to go. Take the butter out of the refrigerator before measuring all the ingredients. This recipe is simple but it does require seamless execution.
1. Sugar Syrup. Mix half of the sugar with the water in a medium saucepan over medium heat, stir just until the sugar dissolves.
When the pan heats up, brush around the sides of the pot with a clean pastry brush dipped in water to dissolve any sugar crystals adhered to the sides of the pot. You can also use a paper towel that you roll up.
When your sugar starts to bubble, begin whipping your egg whites in the bowl of a stand mixer fitted with the whisk attachment.
2. Meringue Mixture. You also want to make sure that your mixing bowl is clean (glass or metal, not plastic) and free of any residual fat, or your meringue will not mix up.
You can add a pinch of salt and/or cream of tartar for stability if you wish.
When your eggs begin to look frothy, slowly begin adding the second half of the sugar, whipping constantly on medium-high.
Continue whipping your egg whites until they form stiff peaks.
3. Timing. Ideally, your meringue should reach stiff peaks at the same time that your sugar syrup reaches 235 degrees F.
If your egg whites are whipping too fast, reduce the mixer speed to medium.
You can also adjust the heat on the sugar syrup to make it cook faster or slower.
4. Pouring the Sugar Syrup. Turn your mixer up to high and SLOWLY pour the sugar syrup down the side of the bowl. Be very careful not to hit the whisk.
Ideally, you should pour it in one solid stream down the edge because it will solidify where it hits the bowl, so if you pour it in three different places, you will be losing sugar.
5. Whipping. Keep whipping the Italian meringue on high until it forms stiff peaks. The temperature of the meringue is important prior to adding the butter.
6. Butter. Before you begin adding the butter, the bottom of the bowl should feel barely warm.
Take your cubed butter out of the refrigerator when you begin measuring the ingredients.
Switch to the paddle attachment and begin adding your butter a piece at a time.
Before adding each piece, squeeze the butter. (Do not cream or soften the butter prior to adding it to the mixture.)
Continue to beat the butter on medium-high until the buttercream is smooth and there are no remaining pieces of butter.
7. Flavorings. At this stage, switch back to the whisk, add flavorings and beat it until it is light and fluffy.
Pipe or spread as desired.
When your butter has been completely incorporated, pour your chocolate in all at once and immediately fold it in with a spatula or beat it in with the paddle attachment.
You want to make sure that your chocolate is melted but not hot and it is also still warm enough to flow freely in a continuous stream.
If your chocolate is too hot, you will melt your butter cream; but if it is too cool, then you will have pieces of chocolate in your frosting.