Why It Works
- Sugar keeps the egg whites' moisture content in check, for a glossy and stable meringue.
- Toasted sugar brings the overall sweetness into balance, adding complexity of flavor.
- Cream of tartar is acidic, adding a counterpoint to the sweetness of the meringue.
- Cooking to 175°F (79°C) ensures that the egg white proteins are coagulated despite the high concentration of sugar, creating a more stable meringue.
With the right technique, Swiss meringue is fluffier than a French meringue made with the same ratio of ingredients, and every bit as stable as its Italian cousin. The trick is to warm the egg whites and sugar over a gently simmering water bath. With toasted sugar, cream of tartar, plenty of salt, and a little vanilla, the finished meringue whips up with lots of flavor, aroma, and a well-balanced sweetness, too. Use it in your favorite recipes for meringue cookies, Swiss buttercream, pavlova, and any meringue-topped pie.
- 6 ounces egg whites (2/3 cup; 170g), from 5 to 6 large eggs
- 9 ounces plain or lightly toasted sugar (1 1/4 cups plus 1 tablespoon; 255g) (see note)
- 1/4 teaspoon Diamond Crystal kosher salt; use half as much if iodized
- 1/4 teaspoon cream of tartar
- Scraped seeds from 1 split vanilla bean (optional)
Fill a wide pot with at least 1 1/2 inches of water, with a thick ring of crumpled tinfoil placed inside to act as a "booster seat." Place over high heat until steaming-hot, then adjust temperature to maintain a gentle simmer. Combine egg whites, sugar, salt, cream of tartar, and vanilla seeds (if using) in the bowl of a stand mixer. Set over steaming water, stirring and scraping constantly with a flexible spatula, until egg whites hold steady at 175°F (79°C), between 8 and 10 minutes. Transfer to a stand mixer fitted with a whisk attachment and whip at high speed until meringue is glossy and beginning to ball up inside the whisk, about 5 minutes. Use immediately.
You can toast the sugar for this meringue in just 30 minutes with my "quick" technique or use sugar as a pie weight to toast it passively. In that case, after transferring the sugar to a new container, check to make sure it's grease-free by running a finger across the interior of the foil lining. If it feels greasy, it means the sugar was exposed to the dough and able to wick away some of the butter. While trace amounts of fat won't prevent Swiss meringue from foaming, they will adversely impact its overall volume and stability.