Before we get started, I do want to point out that this is the type of recipe where you should definitely read through all of the instructions and notes before you start putting it together. Especially if you want to learn how to make a Swiss Meringue Buttercream, but have never made one before. It’s not that anything in this recipe is difficult to do. Rather, successfully making a Swiss Meringue Buttercream requires a higher level of attention to detail and the following of some methodical steps as part of the process. But the end result is so worth it. You’ll see!

What is Swiss Meringue Buttercream? Swiss Meringue Buttercream is a luxurious frosting crafted from cooked egg whites, sugar, butter, and flavorings like vanilla, salt, or in this case, peanut butter. Its silky-smooth texture and delicate sweetness make it a popular alternative to overly rich American buttercream. This versatile European-style frosting boasts a professional appearance and a light, airy consistency that holds its shape beautifully.

While requiring (only) slightly more patience than its American counterpart, Swiss Meringue Buttercream is remarkably stable and requires only a few basic ingredients. The result is a spectacular frosting that elevates any dessert from cakes and cupcakes to beyond!

This particular Swiss Meringue Peanut Buttercream offers a delightful balance of flavor and texture that will impress even the most discerning palate — especially when paired with our favorite Moist Chocolate Cupcakes.

Here at the New England Innkeeper headquarters, we make these often, and it’s always so rewarding to watch our friends enjoy them. To see the way faces change about halfway through their first bite of these Moist Chocolate Cupcakes with Swiss Meringue Peanut Buttercream. Without fail, people can’t believe how light, how velvety, how perfectly flavor-balanced, and how indulgent a simple cupcake can be. It always catches them by surprise. Completely unexpected. It’s not that these cupcakes don’t look AMAZING at first glance. They look ABSOLUTELY AMAZING! But they taste EVEN BETTER and they’re always gone before you know it!

For the cupcakes

We prefer to use natural parchment cupcake liners (click here). These have no colors/bleaches/dyes to be concerned about – plus they release from the cupcakes very easily. Much better than most widely available supermarket brands.

For muffin tins, we are particular. For health reasons, we never use any products with toxic nonstick (or similar nano-ceramic, etc. style coatings). We have a discontinued Pampered Chef stoneware muffin pan that we love — and if you can find a used one in good condition, we highly recommend you snatch it up! We are also avid cast iron users – and these Lodge Cast Iron Muffin Pans are completely toxin-free and represent an excellent value for a lifetime of usability. We also have a couple of vintage (1970s-era), time-worn, and commercial-sized (24 cavity) Chicago Metallic muffin pans (552D) that have served us well for years of every-single-day baking for guests at the inn AND for our own household use. They’re heavy duty steel, un-coated, and well-seasoned from decades of daily use. I’m pretty certain they don’t make these with the same materials or quality these days, but if you can find one of the older/vintage versions that pop up on eBay or Etsy from time to time, you should definitely consider a purchase.

In the New England Innkeeper kitchen, we always use Vollrath #16 2oz (blue handle) scoops/dishers to consistently portion our muffins and cupcakes.

For the Swiss Meringue Peanut Buttercream

When it comes to mixing bowls that work well for a bain-marie / double-boiler setup, we have found this Cuisinart set to be durable — and this All-Clad set to be durable AND gorgeous!

Our most-trusted infrared thermometer is this Fluke model. We also love the widely acclaimed ThermoWorks Thermapen instant read thermometer.

For this recipe, and many other cupcake recipes, our favorite piping tips are the Wilton 1M (Open Star), Wilton 2D (Drop Flower), Ateco 846 (Closed Star), or Ateco 849 (Closed Star) tips.

Can you make this Swiss Meringue Peanut Buttercream in advance? Absolutely. For short-term storage, keep it in an airtight container at room temperature for up to 2 days. For longer freshness, refrigerate the frosting in an airtight container for up to 2 weeks. Even though we don’t really recommend it, you could plan even further ahead and freeze the frosting in an airtight container for up to 3 months. When ready to use frozen frosting, thaw the Swiss Meringue Buttercream overnight in the refrigerator. Then remove from the refrigerator, allow to warm/thaw completely at room temperature (about 72°F). If necessary, beat with a paddle attachment for 2-3 minutes until smooth and creamy.

How long can these cupcakes with Swiss Meringue Buttercream sit out? These cupcakes can be stored covered at room temperature for up to 2 days.

How to store these Moist Chocolate Cupcakes with Swiss Meringue Peanut Buttercream for longer periods of time? Refrigerating the freshly frosted cupcakes (uncovered) immediately afterwards for a short stint can help the Swiss Meringue Buttercream set more effectively, particularly on hot summer days or in humid conditions. To store longer without sacrificing flavor/texture, you can refrigerate them for up to five days — cover them with plastic wrap or in an airtight container once the frosting has initially cooled down and set. When serving, allow the cupcakes to come to room temperature for about an hour before serving, as Swiss Meringue Buttercream is most enjoyable at room temperature; cold buttercream can become overly firm and lose its smooth, creamy quality.

Swiss Meringue Troubleshooting

What are your best tips for successfully making this Swiss Meringue Peanut Buttercream? Be certain to quickly wipe down your mixing bowls, whisks, paddles, and spatulas with lemon juice or vinegar to ensure they’re detergent-free and grease-free, as any residue can hinder meringue formation, making it tougher to achieve stiff peaks. Separate eggs when cold for easier handling (using the “three-bowl method”, outlined in the recipe notes below) —  and let the egg whites rise to room temperature before using them in your recipe. Heat the egg white and sugar mixture to 165°F and use the fingertip method (listed as an “additional cue” in the recipe below) to verify complete sugar dissolution before removal from the double boiler. Whip the meringue with the whisk attachment until it forms stiff peaks. Ensure your butter is truly at a 65-68°F room temperature and then incorporate it gradually, a few tablespoons at a time at a time. Finally, mix the finished buttercream on the lowest speed with a paddle attachment to eliminate air bubbles and achieve a smooth texture ideal for cake frosting.

How can I fix Swiss Meringue Buttercream that looks curdled? If the frosting looks curdled while you’re preparing it, persistent mixing will often solve the problem. This is because Swiss Meringue Buttercream appears curdled when either the ingredient or ambient room temperatures are too low. If a few additional minutes of mixing doesn’t bring the meringue together, then place the bowl over a hot water bath or double boiler until the frosting around the edges of the bowl begins to melt. Then stir vigorously on medium speed for approximately 5 minutes. The melted, warm frosting will blend with the colder portion, gradually raising the overall temperature and achieving a smooth consistency.

How can I fix Swiss Meringue Buttercream that looks soupy or watery and doesn’t form stiff peaks? If your frosting becomes soupy and runny, it’s likely because the meringue was too warm when you added the butter, the butter itself was too warm, or your kitchen is too hot and humid. To salvage it, chill the mixing bowl and your whisk attachment in the refrigerator for 10-20 minutes. During this time, the buttercream around the sides of the bowl should firm up, though the center might still be a bit soft. Remove it from the refrigerator and mix the buttercream for a few minutes; if it remains too soft, chill it for another 10 minutes and then mix it again. This usually helps the buttercream achieve the right consistency. If it still doesn’t form stiff peaks, you may have started the recipe using baking tools with grease or detergent residue on them (this is why we advise that you thoroughly clean and rinse the, then wipe them down with vinegar or lemon juice before beginning. The other concern that could stop you from achieving stiff peaks is if your egg whites are contaminated with some egg yolks (this is why we advise you to separate the eggs while they are cold using a “three bowl method” (which is outlined in the recipe notes below). If your egg whites are contaminated with grease, detergent, or egg yolk, you may find that you are unable to get the meringue to form stiff peaks and may have to start over.