• There are two ways to make 7 minute frosting. One way is with a double boiler. I will give these instructions first. Another way is without a double boiler. This is the way I make my 7 minute frosting. You will need a saucepan, a heatproof glass or metal mixing bowl that fits snugly on top of the saucepan (this can be a stand mixer bowl), a handheld mixer if you do not have a stand mixer, and a candy thermometer.

No Double Boiler Method

• Fill a saucepan with 1-2 inches of water over medium-high heat, as with the double boiler method. You will be using a heat-proof glass or metal mixing bowl, so be sure the bottom of the bowl does not touch the water and that there is a tight seal between the bowl and the pan. Again, you want steady, indirect steam.
• Add the egg whites, sugar, salt, water, and cream of tartar to the mixing bowl. Whisk to ensure there are no lumps of sugar or cream of tartar. Attach the candy thermometer to the side of the bowl.
• Place the heatproof bowl over the simmering water. Continuously whisk the frosting ingredients to ensure the egg whites don’t cook and to ensure even heating. Keep a close eye on the candy thermometer. You want the mixture to reach 160°F or 71°C. This will take about 3 minutes. This temperature means your egg whites are pasteurized. Carefully remove the bowl from the heat.
• If you are using a stand mixer, use the whisk attachment and start at the low-speed setting, gradually increasing the speed to high. This process will take about 7 minutes to form stiff peaks, and the frosting has tripled in volume. Add the vanilla and mix just until incorporated and no vanilla streaks remain. Use the frosting immediately.

Double Boiler

• Fill the bottom of the double boiler with 1-2 inches of water. Ensure the water level is low enough that it doesn’t touch the bottom of the top part when it’s placed over it.
• Place the bottom of the double boiler over medium-high heat and bring the water to a gentle simmer. (The goal is to have steady steam without a rolling boil.) You will need to adjust the heat to keep the water just simmering.
• Before you place the top part of the double boiler over the bottom part, add the egg whites. Gradually whisk in the granulated sugar and salt.
• Whisk in the water. This will help dissolve the sugar and create a smoother mixture.
• Finally, sprinkle in the cream of tartar. This will help stabilize the egg whites and ensure the right consistency when whipped. Be sure to whisk the egg white mixture thoroughly so there are no lumps, and the mixture is smooth.
• Place the top part of the double boiler over the simmering water. Be sure the bottom of the top part of the double boiler does not touch the simmering water. (You want gentle, indirect heat from the steam. You don’t want the egg whites to get too hot too quickly.)
• Use either a whisk or a handheld mixer to start beating the mixture at low speed. Gradually increase the speed to high. Continuously beat until the mixture becomes glossy, triples in volume, and holds stiff peaks. (This process should take about 7 minutes.) Once the frosting reaches the desired consistency, carefully remove the top of the double boiler from the simmering water. Continue beating the frosting for another minute or two until the frosting has slightly cooled.
• Add the vanilla and mix just until well incorporated. Use the frosting immediately.