Makes about 400g, or 2 cups, of buttercream. Enough to generously frost 8-10 cupcakes.
Ingredients
100g (or ½ cup) granulated sugar
3 tablespoons water
5 large egg yolks (or 85g, about ⅓ cup)
226g (or 1 cup) unsalted butter, softened at room temperature
¼ teaspoon vanilla extract
a pinch of table salt, optional
Instructions
Combine sugar and water in a medium-sized saucepan. Heat over low heat, stirring with a metal spoon until the sugar has dissolved and the syrup is clear. Crank up the heat to medium-high and allow syrup to come to a boil.
In the meantime, place yolks in a medium-sized, heatproof bowl and mix (with an electric mixer fitted with the whisk attachment) until thick and foamy.
Once the syrup has come to a boil, clip on a candy (or sugar) thermometer. Cook until the syrup reaches 114°C/238°F, then immediately remove from the heat and slowly drizzle the hot syrup into the bowl with the yolks, mixing continuously to prevent the yolks from scrambling. Don't pour the syrup onto the whisk, or the syrup may splatter against the sides of the bowl (or into your face). Instead, aim for a spot close to the whisk.
Once all the syrup has been added, keep mixing until the bottom of the bowl feels cool to the touch and the pâte à bombe (aka: yolk meringue) has cooled down to room temperature.
To incorporate the butter using the beaten butter method, beat the butter in another medium-sized bowl, using an electric mixer fitted with a whisk or paddle attachment, until pale and fluffy, about 2 minutes. Add the cooled pate au bombe one tablespoon at a time, mixing well after each addition. Once all the butter has been added, add the vanilla and salt and mix for another 5 minutes, or until the buttercream looks smooth and creamy.
Use immediately or store in an airtight container or a zipper bag in the fridge for up to two weeks or in the freezer for up to two months. To use buttercream that has either been refrigerated or frozen, first allow it to come to room temperature then beat it with a mixer until it's smooth and spreadable again. Cakes or cupcakes decorated with buttercream generally keep up to 3 days, stored in an airtight container in the fridge. Always allow buttercream, or cakes frosted with buttercream, to come to room temperature before serving!
Notes
* To incorporate the butter using the cubed butter method, start adding the butter one tablespoon at a time, mixing well after each addition. Once all the butter has been added, mix for another 5 minutes, or until the buttercream looks smooth and creamy. If the buttercream separates, just keep mixing like you mean business and the buttercream will come together again.