Wipe the metal bowl of an electric stand mixer, whisk attachment and a whisk with vinegar or lemon juice and a paper towel to remove any trace of grease.
Fill a large pot with 1 inch of water and bring to a boil, then reduce to a simmer. Place a metal mixing bowl over the pot of simmering water (bowl should fit snugly but should not touch the water) and add egg whites and sugar. Stir constantly with a whisk until the temperature reaches 140 degrees or until all the sugar has dissolved. Remove from heat.
Add the cream of tartar and beat the egg white mixture on high speed until the bottom of the bowl is completely neutral, about 10 minutes.
Prep a pastry bag with icing tip of your choice and fill with merengue. Pipe and gently toast with a kitchen torch.
Recipe by oh honey bakes at https://ohhoneybakes.com/chocolate-stout-speculoos-cake/