Swiss Meringue Buttercream Frosting Recipe

Chef's Notes

Yield: Makes about 5 cups or enough frosting for a two-layer 8″ or 9″ inch cake, about 12 cupcakes with a tall cloud of frosting piped onto it, or about 24 cupcakes if you are just spreading a smaller amount of frosting on them with a knife.
Make Ahead: Swiss meringue buttercream can be left out at room temperature for up to 2 days, so it’s great for making ahead. To store Swiss meringue buttercream, transfer it to an airtight container. If refrigerating or freezing, let it come to room temperature and then whip it again until it’s smooth and creamy.
Storing: SMBC can be refrigerated for 1-2 weeks and it freezes beautifully for up to 3 months, so you can even make extra batches to have on hand for occasions when you know you are likely to be pressed for time. Just be sure if refrigerating or freezing buttercream frosting that you let it sit out at room temperature for 3-4 hours to thaw completely, then beat it again with your mixer so it is fluffy, spreadable, and smooth before using.
Troubleshooting runny SMBC: This can happen if the butter was too soft or if the meringue was not whipped to stiff peaks or was still too warm when adding the butter. To fix this, place the buttercream in the refrigerator for 15-20 minutes to firm up the butter, then whip it again with a stand mixer or hand mixer until it thickens to the desired consistency. If it is still soupy, stick it back in the fridge for longer to cool down.
Troubleshooting curdled or separated SMBC: This can happen if the butter was too cold or if it was added too quickly to the meringue. To fix this, keep beating for 5 minutes! Or if it is still a problem, you can remove a small portion of the curdled buttercream (about 1 cup) and microwave it for a few seconds (like 10 to start) until it is melted but not hot. With the mixer running on low speed, slowly pour the melted buttercream back into the mixing bowl and continue to mix until the frosting is smooth and creamy. Another option is to stick the bowl back over simmering water and let it sit for 1-2 minutes. This will melt the butter around the outside edges of the bowl without melting the frosting in the middle. Once you mix everything together it should smooth things out
Trouble shooting SMBC that is too sweet: To fix this, try adding an extra pinch of salt to balance out the sweetness. You can also try adding up to ½ cup additional butter without changing any of the other ingredients to dilute the sweetness and increase the butter ratio. Personally I have never had this be an issue for me with SMBC, but I also like really sweet frostings like American buttercream
Fruit Variation: You can add up to about ¼ cup of fruit puree, such as raspberry, strawberry, or mango, to SMBC to create a fruity frosting. Be sure to strain the puree to remove any seeds or pulp before adding it to the buttercream. Another option is to use freeze-dried fruit that has been ground into a fine powder.
Chocolate Variation: To make chocolate Swiss meringue buttercream, add 6 ounces of melted, cooled semi-sweet or bittersweet chocolate to the buttercream after mixing in all of the butter and vanilla extract. Mix on low speed until fully incorporated, stopping to scrape down the sides of the bowl as needed. Once the chocolate is combined with the other frosting ingredients, increase the speed to medium and mix until the chocolate Swiss meringue buttercream is smooth and creamy. You can also add up to 2 Tablespoons of cocoa powder along with the melted chocolate for an even more intense chocolate flavor.
Caramel Variation: To make caramel SMBC, add ½ cup of homemade caramel sauce or store-bought caramel sauce to the buttercream.
Citrus Variation: 1-2 Tablespoons of lemon zest, lime zest, or orange zest can be added to SMBC for a tangy and refreshing flavor.
Almond Variation: Add ½ to 1 teaspoon almond extract to SMBC for a nutty flavor.
Other extracts: Mint, orange, raspberry, coconut, cherry, rum, or other extracts can be added for more flavor variations. For these stronger extracts, I would recommend starting with ½ teaspoon and going from there.
Spices: Cinnamon, nutmeg, ginger, apple pie spice, or pumpkin pie spice can be added to SMBC to create a warm and cozy flavor.
Nutrition: The nutrition information was calculated using an online tool based upon dividing the frosting into 12 servings (enough for 1 cupcake with a big swirl of frosting on it or one slice of cake). However, I am not a nutritionist and for the most accurate results, you may want to do your own calculations.