Seven-Minute Frosting

Before you start

Seven-minute frosting is a cooked meringue: egg whites, sugar, water and a little cream of tartar are beaten together in a bowl set over simmering water until the mixture turns thick, white and glossy. The name comes from the approximate beating time with a hand mixer. There is no butter, so it is light and sweet, with a soft, marshmallow-like texture that forms tall swirls and peaks.

The key is heat and constant motion. Beating while the bowl heats dissolves the sugar and cooks the whites; aim for 71°C (160°F) on a thermometer. Spread it right away, because it begins to set and form a thin crust within an hour, which is part of its charm on an old-fashioned coconut cake.

Ingredients

• 2 large (about 60 g) egg whites — room temperature
• 300 g (1½ cups) granulated sugar
• 80 ml (⅓ cup) cold water
• ¼ tsp cream of tartar
• 1 pinch fine salt
• 1 tsp vanilla extract

Method

1. Bring 5 cm (2 in) of water to a gentle simmer in the saucepan. The bowl should sit on the pan without touching the water.
2. Off the heat, combine the egg whites, sugar, cold water, cream of tartar and salt in the bowl. Beat on low for 1 minute until frothy and the sugar is moistened.
3. Set the bowl over the simmering water and beat on high speed, moving the beaters around the whole bowl and scraping the sides with a spatula every minute so no sugar or egg sticks and overcooks.
4. Keep beating for 6 to 8 minutes, until the frosting is bright white, thick and glossy, holds stiff peaks and reads 71°C (160°F) in the center. Lifting the beaters should leave a firm, curved peak.
5. Take the bowl off the pan, add the vanilla and beat for 1 to 2 minutes more, until it cools slightly and thickens a little further.
6. Spread the frosting on the cooled cake immediately, using the back of a spoon or an offset spatula to make swoops and peaks. It sets as it cools, so work quickly.

Tips for success

• A completely grease-free bowl and beaters are essential. Any trace of fat or yolk keeps the whites from whipping fully.
• Rub a little of the frosting between your fingers before taking it off the heat. If it feels gritty, the sugar has not dissolved; keep beating.
• Frost the cake on the day you serve it. The frosting is at its fluffiest within the first few hours.

Substitutions

Cream of tartar

Use 1 tbsp light corn syrup or ½ tsp lemon juice. Both help keep the sugar from crystallizing; lemon adds a faint tartness.

Granulated sugar

Replace 50 g of the sugar with light brown sugar for a gentle caramel flavor and a pale beige color.

Fresh egg whites

Pasteurized liquid egg whites work but can take a few minutes longer to reach stiff peaks.

Variations

Toasted seven-minute frosting

Frost the cake, then brown the swirls lightly with a kitchen torch for a toasted-marshmallow look and flavor.

Coconut cake finish

Press 120 g sweetened shredded coconut onto the sides and top of the freshly frosted cake before the frosting sets.

Troubleshooting

Frosting stayed soupy after 8 minutes

The water was not hot enough or the bowl was too large and shallow. Keep the water at a steady simmer and keep beating; it can take 10 minutes or more.

Grainy texture

Sugar crystals were left undissolved or scraped from the bowl sides. Scrape regularly and beat until a pinch feels smooth.

Frosting weeps or slides off the cake

It was undercooked, or the cake was still warm. Cook to 71°C (160°F) and frost a fully cooled cake. Humid weather also makes it weep; serve the same day.

Storage

Seven-minute frosting is best eaten the day it is made. Keep a frosted cake loosely covered at cool room temperature for up to 1 day, or refrigerate it for up to 2 days; it may weep slightly and lose some volume. Do not freeze.

Safety notes

The whites are cooked over simmering water; heat the frosting to 71°C (160°F), the temperature FDA recommends for egg dishes. Contains egg.