View Large Image Swiss Buttercream Icing Recipe Get ingredients: 454 g (2 cups) butter (unsalted, room temperature, around 65° F / 18° C) 5 egg whites (large, room temperature) 1 g (1/4 tsp) cream of tartar (or lemon juice or white vinegar) 227 g (1 1/3 cups) chocolate (dark, 70-99% cacao) (optional) 3 g (1 tsp) kosher salt (or 3 g (1/2 tsp) table salt) 333 g (1 2/3 cups) sugar (white, granulated) 4 g (1 tsp) vanilla extract (pure) stand mixer thermometer mixing bowl (large) (glass or stainless steel) saucepan (large; big enough to fit stand mixer bowl for a double boiler) spatula whisk If the eggs are not room temperature, place them in a bowl of warm water for a few minutes. Ensure the large mixing bowl, stand mixer bowl, whisk attachment, and a small bowl (for separating eggs) are clean and dry. Attach the whisk to the stand mixer. Fill the saucepan about 1.5 inches deep with water. Ensure the large mixing bowl fits on top of the saucepan with a gap between the bottom of the bowl and the water. If the bowl touches the water, crumple some aluminum foil into a donut shape and place the aluminum foil in the saucepan to create a booster seat for the mixing bowl. Do not use the stand mixer bowl. If you use the same bowl for mixing later, it will take too long to cool down. Do not use a plastic bowl (it will melt), an insulated stainless steel bowl (it will take a very long time to heat up), a bowl with a silicone bottom (it may fuse to the saucepan), or a ceramic bowl (it will retain heat). Remove the mixing bowl from the saucepan. Place the saucepan on the stove. Set heat to high. After the water is steaming hot (after about 5 minutes), set the heat to medium-low. Separate 5 eggs. Ensure no egg yolks get into the egg whites. Crack an egg over the small bowl. Allow the egg white to pour into the small bowl while keeping the yolk in the egg shell. Once the egg white is in the small bowl, add the egg yolk to an airtight container. Transfer the egg white to the large mixing bowl to prevent yolk from the next egg accidentally getting into the clean egg white. Optionally, store the airtight container with the egg yolks in the fridge to make crème brûlée. Add to large mixing bowl with egg whites: 333 g (1 2/3 cups) sugar 3 g (1 tsp) kosher salt (or 3 g (1/2 tsp) table salt) 1 g (1/4 tsp) cream of tartar (or lemon juice or white vinegar) After the heat has been set to medium-low, place the large mixing bowl over the saucepan. Using a whisk, stir and scrape the sides down occasionally at first as the mixture warms up, and then stir and scrape constantly until the temperature of egg mixture reaches 160-185° F (71-85° C) (about 10-13 minutes). If it's taking too long, turn up the heat. Take some of the mixture and rub between two fingers. If it's gritty, it's not done yet. Remove the bowl from the saucepan. Transfer the mixture to the stand mixer bowl. Attach the bowl to the stand mixer. Mix on high speed until stiff peaks form and the meringue is around 90° F (32° C) (about 5-15 minutes). It's better to under-whip than over-whip. Keep an eye on the height of the meringue at the sides of the bowls. Stop whipping when the meringue stops growing. If it's been 5 minutes and the mixture is still too hot (or if the room is hot), take something from the freezer, like a bag of peas, and wrap it around the outside of the bowl to help cool it down; or put the bowl in the fridge for a minute. Do not put the bowl in the freezer, and do not put the bowl in the fridge for too long. Attach the paddle to the stand mixer. Add to stand mixer bowl: 454 g (2 cups) butter (chopped into about 16 pieces), one piece at a time (wait until each piece disappears before adding the next piece; this only takes a few seconds) The icing will become soupy, but keep adding the butter until it has all been added. Scrape the bowl down once after adding half the butter. The icing will become thick, creamy, soft but not runny, and around 72° F (22° C). It should hang upside down from a spoon without dropping. If it's too warm (the icing is thin and runs off the spoon), put it in the fridge for 10-20 minutes, until the frosting begins to harden around the edges, and then re-whip on high speed until consistent. If it's too cold (the icing is dense, greasy, lumpy, or curdled), briefly place the bowl over a saucepan of steaming water, until the frosting has melted around the edges, and then re-whip on high speed until consistent. Set stand mixer to low speed. Add to stand mixer bowl: 4 g (1 tsp) vanilla extract Mix until well combined (less than 30 seconds). Optionally, for chocolate icing: Measure out (and chop if necessary): 227 g (1 1/3 cups) chocolate Melt chocolate in the microwave until fluid and warm. Add to stand mixer bowl: melted chocolate Mix on medium-high speed until fully incorporated. Using the spatula, scrape the sides of the bowl down to ensure all ingredients have been incorporated. Mix until homogeneous. Use immediately. To store, transfer to a large Ziploc bag, press out air, and seal the bag. Store in the fridge for up to 2 weeks, or in the freezer for several months. To use after storage, re-warm to 73° F (23° C) and re-whip. If it sits for too long at room temperature, whisk manually for 30 seconds.
