Swiss Buttercream

Makes about 10 cups, enough buttercream to generously frost an 8 inch layer cake with room to spare. When it comes to crumb coating and decorating a cake, nothing is worse than realizing you don’t have quite enough buttercream to finish the project. So this recipe errs on the side of plenty. You can freeze any extra buttercream for up to six months and pull it out in a pinch to frost cupcakes or use as a cookie filling.

10 oz egg whites (it’s okay to go a tad over)
10 oz sugar
1/2 tsp kosher salt
the scrapings from 1 vanilla bean
2 pounds unsalted butter, cut into 2” chunks and softened to a spreadable state

Combine the egg whites, sugar, salt, and vanilla bean together in an clean bowl. Set the bowl over a pan of water and turn the heat on medium low. You don’t need the water to even simmer, you just want it hot enough to steam, since steam is what actually heats the whites.

Whisk frequently to prevent an egg white omelet forming on the sides, but continual mixing isn’t necessary. Aim to get the mixture to at least a 145° for food safety reasons, but reaching 150° would make for a nice margin of error. If your egg whites are at room temperature, this won’t take very long, maybe just a few minutes. Whites straight from the fridge will take longer.

When the mixture is sufficiently hot, remove from the heat and use the whisk attachment to whip on medium high speed until the mixture has doubled in volume and turned snowy white. Continue whipping until the meringue is cool. Use your hands to feel the bowl itself, rather than simply testing the temperature of the meringue. You want it to feel perfectly cool to the touch with no trace of warmth. Note: if you are using a glass or ceramic bowl, even if the meringue has cooled, the bowl itself may still be quite warm and continue conducting heat into the buttercream over time. If you are using a glass or ceramic bowl, transfer the meringue to a new bowl before proceeding or continue mixing until the bowl itself is cool.

Turn the mixer down to medium-low and begin adding in the butter, one chunk at a time. If you didn’t let your meringue cool enough, this is when you’ll really regret it. By the time you’ve added all the butter, you may need to scrape down the bowl to fully incorporate any butter or meringue that’s stuck at the sides.

Finally, splash in some vanilla extract or what have you. Just keep adding a 1/4 teaspoon at a time until it suits your tastes.

The buttercream freezes beautifully. To use frozen buttercream, melt about two thirds and put that and the frozen portion in an electric mixer, and whip until fluffy, you might need to melt a bit more if it curdles, or if it's too melty, take some out freeze it again and then whip it in.

Recipe from Bravetart