1 lb (454g) sugar
4 oz (120ml) water
8 oz (227g) egg whites
2 lbs (907g) butter, cut into chunks – room temperature
1 tbsp (15ml) vanilla extract

Combine 12 ounces sugar and water in a heavy bottomed saucepan and bring to a boil over medium-high heat, stirring to dissolve the sugar and then cook without stirring until the mixture reaches soft-ball stage (240F or 116C).

While this is happening, place your egg whites in the bowl of your stand mixer set up with a whisk attachment. The timing of this is a careful thing so when your sugar syrup is reaching the temperature around 225-230F, you want to whip your egg whites until they’re frothy and add the remaining 4 ounces of sugar and beat until the meringue reaches medium peaks. When the syrup hits 240F, slowly add it to the meringue in a steady stream while continuing to mix the meringue at a medium speed. Once all the syrup is added, increase the speed to high and continue to whip until the meringue has reached room temperature and the bowl is cool to the touch. Add the soft butter gradually, a chunk or two at a time until it is fully incorporated. Scrap down the sides of the bowl after a few additions, add the vanilla and mix well.

There will likely come a point where the mixture will look curdled. Don’t panic! If you haven’t added all the butter yet, continue to do so. If you have, let the mixer do it’s work and keep mixing. It may take a minute but the mixture will become smooth and even. Add your flavorings and if you’re not using immediately, refrigerate in a tightly covered container.

I’ve had chocolate, chocolate rum, praline, mocha, pineapple, vanilla, hazelnut, chestnut, raspberry, and even green tea buttercream.