Silky Swiss Buttercream

1. Prepare Water Bath

Fill a wide pot with about 1.5 inches of water and crumple some tinfoil to place at the bottom. Heat the water until it becomes steaming-hot but not boiling.

2. Combine Ingredients and Heat

In the bowl of your stand mixer, combine egg whites, sugar, salt, cream of tartar, and vanilla seeds if using. Place this bowl over the steaming water bath. Stir continuously with a flexible spatula until the mixture reaches a temperature of 185°F, about 10-12 minutes. The mixture should become glossy and smooth.

3. Whip the Meringue

Transfer the bowl to your stand mixer fitted with a whisk attachment. Whip on high speed until the meringue is glossy, stiff, and cool to the touch, about 10 minutes. The meringue should feel around 90°F (32°C).

4. Incorporate Butter

Start adding the softened butter to the meringue, one or two tablespoons at a time, keeping the mixer running. As you incorporate the butter, the buttercream will thicken and become creamy. This step is done when the mixture reaches about 72°F (22°C).

5. Add Extracts

Mix in the vanilla extract, and almond extract if using, on low speed until everything is well combined.

6. Store or Use

Your silky Swiss buttercream is now ready to use. You can either use it immediately or transfer it to a zipper-lock bag for storage. Refrigerate for up to two weeks or freeze for several months. If your buttercream becomes too warm and starts to separate, refrigerate it for about 15 minutes before re-whipping. Conversely, if it's too cold and stiff, set it briefly over steaming water and then re-whip.