Italian Meringue Buttercream
Italian meringue buttercream (IMBC) is a thick and creamy frosting made by whipping egg whites with a hot sugar syrup and softened butter. It's silky smooth, barely sweet, and stable enough for wedding cakes and warm weather.
Servings: 8 cups
Calories: 846kcal
Equipment
- Stand mixer with the whisk attachment
- Candy Thermometer
Ingredients
- 16 ounces granulated sugar
- 8 ounces water
- ¼ teaspoon salt
- 8 ounces egg whites (about 8 large egg whites separated from the yolk)
- 24 ounces unsalted butter softened
- 2 teaspoon vanilla extract
Instructions
- Before you begin: Make sure your butter is softened to room temperature and your mixer bowl and whisk are completely grease-free (wipe them with a little lemon juice or white vinegar). Have your candy thermometer ready.
Make the Buttercream
- On the stovetop, mix together the water and sugar, cover with a lid and bring to a boil on medium-high heat.
- Keep the lid on the pot for 3 to 4 minutes while the mixture simmers to ensure all the sugar granules are dissolved, otherwise, your sugar can get gritty and crystalize. DO NOT MIX.
- Remove the lid, insert the candy thermometer carefully and continue cooking on medium-high until the syrup reaches 240º F.
- When the sugar solution is at about 235º F, begin whipping the egg whites on high speed. Add the salt to the egg whites.
- When the egg whites reach soft peaks, pour the sugar solution in a steady stream on to the whipping whites while mixing on low speed.
- Continue whipping the egg/sugar mixture until it reaches stiff peaks. I wrapped an apron around my bowl with an ice pack to help the meringue cool down faster. You can also cool the meringue by scooping it out of the bowl and placing it into the fridge for 15 minutes.
- Once the meringue is cooled, whip in soft butter and vanilla until the buttercream is light and fluffy and no longer has a butter taste. This can take from 10 to 15 minutes. If it looks curdled and watery just keep whipping. It will come together I promise.
Video
Notes
Make sure your sugar syrup reaches exactly 240º F. Under-cooking it will result in a soft, unstable buttercream that won't hold its shape.
Keep the lid on the pot for the first few minutes to prevent sugar crystals from forming on the sides of the pan.
Begin whipping your egg whites when the syrup hits 235º F so they reach soft peaks right as the syrup is ready.
The meringue must be completely cool to room temperature before adding butter or the buttercream will become soupy.
Use softened but not melted butter. It should hold its shape but give easily when pressed.
If the buttercream looks curdled or soupy, keep whipping. It will come together.
Storage: A cake frosted with Italian meringue buttercream is safe at room temperature for up to 24 hours. Refrigerate leftover buttercream for up to 2 weeks or freeze for up to 6 months. Bring to room temperature and re-whip with the paddle attachment on low to smooth out the air bubbles.
For extra stability in warm climates, replace up to half the butter with solid vegetable shortening.
Color and flavor: Add gel food coloring at the end. Add chocolate, espresso, or freeze-dried fruit only after the buttercream is completely finished.
Nutrition
Serving: 2ounces | Calories: 846kcal | Carbohydrates: 57g | Protein: 4g | Fat: 69g | Saturated Fat: 44g | Polyunsaturated Fat: 3g | Monounsaturated Fat: 18g | Trans Fat: 3g | Cholesterol: 183mg | Sodium: 131mg | Potassium: 69mg | Sugar: 57g | Vitamin A: 2125IU | Calcium: 24mg | Iron: 0.1mg
