This Swiss Meringue Buttercream is easy to make, perfectly sweetened and has a light, silky texture. It is the perfect topping for cakes or cupcakes! It’s silky texture makes it the best frosting to achieve that perfectly smooth coating on a layer cake.
Heat about an inch of water up in a medium sauce pot until it is just about simmering. The most important thing is that the bowl of your stand mixer should fit inside so that it is “nested” but the water does not touch the bottom of the bowl.
Whisk together egg whites, salt and sugar. Then place the bowl over top of simmering water and continue whisking constantly. Cook the whites and sugar just until it reaches 130°F on an instant read thermometer or until the sugar has dissolved and the mixture is warm to the touch. The meringue will have started to gain a bit of volume and feel lighter at this point as well.
Move the bowl to your stand mixer and fit with the whisk attachment. Be careful and use a towel because the bowl will be hot if you have a gas burner! Beat on high speed until the meringue reaches stiff peaks and cools slightly.
Switch to the paddle attachment and then add all the butter. Beat on medium until all the butter works itself into the meringue and a silky smooth buttercream forms.
If there are a few stubborn bits of butter, you can gently heat the sides of the bowl with a kitchen torch and it will melt those remaining pieces. Don’t do it too much or for too long in one spot, or the other butter will melt and you can’t come back from that.
If you add your butter when your meringue is too warm, and you now have a soup, don’t stress! Let the butter work in completely (or it will solidify in the fridge and you’ll then have a chunky buttercream) and then pop the whole bowl and attachment in the refrigerator for about 20-30 minutes. Continue the mixing process. The NUMBER ONE RULE is be patient!
Once your buttercream comes together, switch back to the whisk and add your vanilla. Beat it up until it is light and fluffy! Frost away!
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Notes
Yield: 1 ½ quarts, or enough to frost a 6-8 inch cake.Variations – Add up to ¾ cup jams or jellies, caramel sauce or lemon curd. Add up to ½ cup nut butters or 7 oz chocolate, melted but not hot.Storage – Store in a clean container in the refrigerator for up to 2 weeks or frozen for up to 3 months. SMB can also be left at room temperature overnight.