This is the only meringue recipe that has ever worked for me, and i have tried Many. Translated and adapted from here.
This recipe works best if you use older eggs, and if you separate the whites from the yolks the day before making these.
An amount (original recipe claims 20, but it depends on the size of the meringue).
Make sure that the egg whites have been left out of the fridge for at least 15 minutes.
Preheat oven to 120°C.
Add the salt to the eggs and beat until you have soft peaks.
Gradually add half the sugar to your eggs, while continuing to beat them. Beat until you have stiff peaks.
Gradually add the rest of the sugar, and continue to beat the eggs until all of the sugar is mixed in.
Spoon the mixture into kisses on some baking paper. The meringues won’t spread much as they cook, but try to make sure they’re not touching.
Cook for 45 minutes to an hour.
This recipe is lactose free and gluten free. You really really want an electric whisk for this. Caster sugar should also be fine, but I haven’t tested this recipe using icing sugar, and it may not work (due to containing starch).