Swiss meringue buttercream is silky smooth, not overly sweet, and it pipes beautifully. The butter also keeps the Swiss meringue stable, allowing your cakes or cupcakes to set out on a counter for hours without any problem.
- 6 large egg whites
- 1 1/2 cups granulated sugar
- 1/8 teaspoons salt
- 3 sticks unsalted butter, close to room temperature*
- 2 teaspoons pure vanilla extract
- If you’ve never made Swiss Meringue or Swiss Meringue Buttercream before, read the tips above this recipe and read the recipe before starting. Wipe clean the large bowl of a stand mixer, making sure the bowl is completely grease-free. Even the slightest amount of grease will prohibit the egg whites from whipping up.
- Separating the egg whites: Make sure the egg whites have absolutely no remnants of egg yolk in them. If there is any egg yolk present, you need to discard the egg white'(s) and start over.
- Cooking the egg whites and dissolving the sugar: Whisk together the egg whites, granulated sugar, and salt in a heatproof, grease-free mixing bowl and place over a saucepan of about 2 inches of simmering water on medium heat. The bottom of the bowl should not touch the water. There should be a seal between the outside of the bowl and the inside edge of the pan. This keeps the steam locked inside under the bowl where it’s needed. Whisk the mixture until all of the sugar has dissolved, about 4 minutes. Test by rubbing a tiny bit of the mixture between two fingers. If it’s gritty, it’s not ready. If it’s smooth it’s ready. You can also test with a thermometer if you’re worried about the egg whites not being cooked to a safe temperature. The thermometer should read 160 degrees.
- Beating & cooling the mixture: Transfer the mixture to the bowl of a stand mixer fitted with the whisk attachment, (if you’re not already using the stand mixer bowl). Turn the mixer to low for about 30 seconds, and gradually turn the mixer up every few seconds until it’s on high speed. Leave the mixer on high and beat the mixture until it forms stiff shiny peaks. This can take anywhere from 12 to 15 minutes, depending on your mixer. The bowl will probably still feel warm. If it does, transfer the bowl, whisk and all, to the refrigerator for about 5 to 10 minutes, and return it back to the stand mixer. If the bowl and meringue are still warm, they will melt the butter when you add it, and you don’t want that.
- Add the butter: Cut the butter into slices. Turn the mixer to high and start adding the butter one slice at a time, allowing the butter to be incorporated before adding more. Once all of the butter is added, mix a few seconds more or until the mixture is very creamy and smooth, turn the mixer to medium and mix in the vanilla.
- Troubleshooting: Too thin: If the buttercream is too thin after you’ve added all the butter, the meringue was probably too warm when you added the butter, thus causing the butter to melt. Place the mixing bowl in the refrigerator for 10 minutes. Return the bowl to the stand mixer and beat on medium-high speed for a couple of minutes and it should thicken up to the correct thicker creamy consistency. Too thick: If the buttercream suddenly looks curdled or extra thick, return the mixture back over the double boiler on medium heat. Heat just for about 1 minute until the edges only of the mixture turns to liquid. Remove from heat and return to the stand mixer. Beat on medium-high speed and beat it for 1 to 2 minutes until it’s smooth again.
- Frost your cake or cupcakes. The buttercream can be left at room temperature for up to 3 days.
- The buttercream can be refrigerated for up to 5 days before using it. Remove it from the refrigerator and allow it to come to room temperature, then beat it with a mixer for about 2 minutes until smooth and creamy again.
- Freezing: The buttercream can be frozen for up to 3 months in an airtight container. Thaw on a counter until it comes to room temperature before mixing, then mix with a mixer until creamy and smooth.
- This recipe makes enough buttercream to frost one 8-inch three-layer cake, one 9-inch two-layer cake, 24 cupcakes if you don’t pipe the buttercream high, or 12 cupcakes if piped high. With most frostings/buttercreams, they are so rich that I don’t pipe them high on cupcakes. However, Swiss meringue buttercream is the exception. It’s so light and not overly sweet that I love a ratio of one big bite of buttercream to one big bit of cupcake.
- *The butter should be a little bit colder than room temperature. It should be soft enough to allow you to easily press your finger into it and leave an indentation, but not so soft that it spreads apart and looks mushy when you leave an indentation. I hope that makes sense.
- Many bakers switch to the paddle attachment before they start adding the butter. Once you start adding the butter, you longer want to incorporate lots of air. A paddle attachment is supposed to add in less air. However, I do use the whisk attachment with no problem with air bubbles, so don’t worry if you want to use the whisk attachment.
- See my notes above this recipe on how to color SMB.
- I highly recommend using a stand mixer for this recipe. It takes several minutes of beating on high speed with a stand mixer to make this buttercream. If you have to use a hand mixer, just be patient. You might have to give your hand mixer a break after a few minutes to let it cool off, and it will take longer.
Keywords: Swiss Meringue Buttercream, Swiss Meringue, Frosting, Buttercream, Vanilla Swiss Meringue Buttercream,