This is an easy way to make a delicious buttercream that is as rich, smooth and perfect as French buttercream. The only difference between traditional French buttercream and this buttercream? You don't need a sugar thermometer.
Ingredients
5 large egg yolks* (about 85ml, or ⅓ of a cup + 1 teaspoon)
100g (or ½ cup) granulated sugar
½ teaspoon vanilla extract
1 teaspoon instant coffee granules
pinch of salt
250g (or 1 cup + 5 teaspoons) unsalted butter, cubed and softened at room temperature
Instructions
Plop the yolks into a medium-sized, heatproof bowl. Add the sugar and immediately whisk until foamy. Add the vanilla and coffee and whisk until combined.
Place the bowl over a pan of barely simmering water (making sure the water doesn't touch the bowl) and heat, whisking constantly, until the sugar has dissolved. You can check whether the sugar has dissolved by rubbing a bit of the mixture between your fingers.
If you want to pasteurize the yolks and make the buttercream salmonella safe (I recommend doing this if you're planning on serving the buttercream to kids under the age of five, the elderly, pregnant women or people with ill health), gently heat the mixture to a temperature of 64°C/147°F, making sure to keep the mixture at that temperature for about 10 minutes to kill the bacteria. You will probably have to repeatedly take the bowl off the heat and put it back on again to regulate the temperature of the mixture. Once you've pasteurized the mixture, proceed with the recipe.
Remove the bowl from the heat and mix (using a mixer) until the mixture thickens and drops in ribbons when you lift the beaters, and has cooled to room temperature. Sprinkle in the salt and mix until combined. You have now made pâte à bombe!
At this point, start adding the softened butter one cube at a time, mixing continuously.
Once all the butter has been added, the buttercream is ready to use. Use it as a filling between cake layers or cookies, or pipe big swirls of this stuff onto cupcakes!
Buttercream can be stored, covered tightly with plastic wrap, in the fridge for up to 1 week (and for up to two months in the freezer, in a zippered bag). To use buttercream that has been chilled, allow it to come to room temperature first, then mix until soft and spreadable again (about 30 seconds).
Notes
*Freeze the egg whites for a later use! Always allow pastries filled or decorated with buttercream to come to room temperature before serving. This may take up to 5 hours, depending on what you're serving (cakes take longer to come to room temperature than cupcakes), but it's worth it! Buttercream is at its absolute best eaten at room temperature!
Recipe by The Tough Cookie at https://thetoughcookie.com/2014/10/27/kitchen-experiment-easy-swiss-french-buttercream/