Make smooth and stable Swiss Meringue Buttercream using egg whites, sugar, and butter for a light, silky frosting perfect for cakes, cupcakes, and macarons. This easy frosting recipe is ideal for decorating, piping, and layering with a clean, professional finish. Great for weddings, birthdays, and special occasions.

Ingredients:

7 oz egg whites (from about 7 large eggs)
2 cups granulated sugar
1 1/2 cups unsalted butter, softened (3 sticks)
2 tsp vanilla extract
1/4 tsp fine sea salt

Instructions:

Prepare the Double Boiler: Fill a medium saucepan with at least 1 inch of water and bring to a gentle simmer.
Heat the Egg Whites and Sugar: In a clean, grease-free stainless steel bowl (preferably from a stand mixer), whisk together the egg whites and sugar. Place the bowl over the simmering water (the bottom should not touch the water) and whisk constantly until the mixture reaches 160˚F. This takes about 3 minutes. The sugar should be completely dissolved—you shouldn’t feel any grit when you rub a bit between your fingers.
Whip the Meringue: Remove the bowl from the heat and dry the bottom. Attach it to your stand mixer fitted with the whisk attachment. Whip on medium-high speed for 15–20 minutes, or until stiff, glossy peaks form and the bowl is completely cool to the touch. It’s essential the meringue is no longer warm before adding butter.
Incorporate the Butter: Switch to the paddle attachment. With the mixer on medium speed, add the softened butter 1 tablespoon at a time, waiting until each piece is incorporated before adding the next. Scrape down the bowl as needed.
Whip Until Smooth: Once all the butter is added, beat on medium-high speed for 3 minutes until the mixture becomes thick and creamy. If the buttercream looks curdled or soupy at any point, just keep mixing—it will come together.
Finish the Buttercream: Add the vanilla extract and salt. Mix on medium-high speed for 1 more minute until fully combined.

Tips

Room Temperature Butter: Make sure your butter is soft but not melted to ensure proper emulsification.
No Grease Allowed: Even a trace of fat can ruin your meringue. Ensure your bowl and utensils are completely clean.
Cool Meringue is Key: Warm meringue will melt the butter and result in a runny frosting.
Consistency Issues? If your buttercream looks off, keep beating—it usually comes together with time.

Variations and Substitutions

Flavor Swaps: Replace vanilla with almond, lemon, or peppermint extract.
Chocolate Version: Add melted, cooled dark chocolate after the vanilla for a chocolate buttercream.
Fruit Buttercream: Blend in fruit puree (strawberry, raspberry, mango) for a fresh twist.
Dairy-Free Option: Substitute dairy-free butter sticks (unsalted) if needed.

FAQs

Can I make this ahead of time?
Yes, store in an airtight container in the refrigerator for up to 1 week or freeze for up to 3 months. Bring to room temperature and re-whip before using.

Why is my buttercream soupy or curdled?
That usually means the butter was added before the meringue was fully cooled, or it just needs more whipping. Keep beating until it smooths out.

Is this buttercream stable for decorating?
Yes, it holds its shape well and pipes beautifully. However, it’s not ideal for extremely hot environments.

Serving Suggestions

Perfect for frosting cakes, cupcakes, and cookies.
Use as a filling for macarons or sandwich cookies.
Swirl on brownies or dessert bars for a bakery finish.

Why You’ll Love This Recipe

Silky texture—light, smooth, and not overly sweet.
Great for piping—holds shapes well and stays soft.
Versatile flavor—pairs with almost any cake or dessert.
Make-ahead friendly—store and freeze for future baking needs.