Preparation Method
- Make the meringue: In the mixing bowl of the stand mixer fitted with the whisk attachment, beat egg whites, cream of tartar, and salt on medium-low (3–4) speed until foamy, about 30 seconds. Increase the speed slowly to high (9–10) until medium peaks form. Slowly add 1/3 cup (67 grams) granulated sugar and continue to beat for 5 minutes.
- While the egg whites are beating, combine 1/3 cup (80 milliliters) water and remaining 1 cup (200 grams) granulated sugar in a small saucepan. Without stirring, cook over medium-high heat until sugar mixture reads 238°F (114°C) on a candy thermometer.
- When the sugar mixture reaches the temperature, reduce the mixer speed to low (1–2) and slowly add the hot sugar mixture to the egg whites. Slowly increase the speed to high (9–10) and beat for 15 minutes to cool the meringue. Leave the meringue in the mixing bowl.
- Make the buttercream: With the mixer on low (1–2) speed, add butter to the meringue one tablespoon at a time, allowing each tablespoon to be incorporated before adding the next. Scrape down the bowl as needed. The buttercream will not look finished until all the butter has been added. Add vanilla extract and vanilla bean seeds. Increase the speed to medium (5–6) and beat for 5 minutes. To clean the buttercream from the whisk attachment, increase the speed to high (9–10) for 10 seconds. Use immediately or store in the refrigerator until ready to use.
Variations
CHOCOLATE MERINGUE BUTTERCREAM
Follow steps 1–3. In step 4, substitute the vanilla bean seeds with 9 ounces (250 grams) melted and cooled semisweet chocolate. To melt the chocolate: In a double boiler over medium-high heat, melt chocolate, stirring frequently. Remove from heat and let cool to room temperature. Add the melted chocolate to the frosting mixture with vanilla extract and continue beating on medium (5–6) speed for 5 minutes.
COFFEE MERINGUE BUTTERCREAM
In step 1, add 3 tablespoons (18 grams) espresso powder to the egg whites. Omit the vanilla bean seeds in step 4.
Pro Tip
For a successful meringue, clean the mixing bowl and whisk in hot soapy water before using to ensure they are free of all fats and oils.
