Add a few drops of lemon juice to the egg whites (this will help the meringue firm up).

Add some water to a pan followed by the sugar and heat over medium heat.

Once the mixture starts to bubble a little, start to whisk the egg whites.

Whisk with a hand mixer on a high speed until the mixer leaves a trail in the meringue. Time your whisking to coincide with the boiling of the syrup mixture. Don't stop whisking though.

Once the syrup reaches 118℃, remove from the heat and dribble into the mixture in thin threads.

Dribble it in so that it falls between to the 2 blades of the mixer, which should be set to a medium-high speed.

Once the syrup is in, keep whisking on a high speed until the mixture cools down.

Once the bottom of the bowl reaches body temperature, it's ready. The peaks of the meringue should hang down a little bit at this point.

For buttercream: Add 50 g unsalted butter to 30 g meringue It can be used for macarons and such.