01 -
Set your oven to 250°F and get a baking tray ready with either parchment or a silicone mat.
02 -
Whisk up the egg whites along with the salt until they start to foam.
03 -
Mix in the gelatin and sugar, then whip until you get stiff peaks. Fold in the vinegar and chocolate chips, if using.
04 -
Spoon or pipe the mixture onto the baking sheet, and decorate with sprinkles if you'd like.
05 -
Pop it in the oven for 30 minutes. Once done, turn off the oven but leave the cookies inside to rest for another 20–30 minutes.
06 -
Take them out and let them cool all the way through.