They have only four ingredients, and you bake them by preheating your oven, then turning it off as soon as you put the cookies in and leaving them in with the door closed for at least 4 hours. You can just leave them in the oven overnight if you'd like to wake up to cookies in the morning!
Grandma's Cloud Cookies
6 egg whites
1 1/2 C granulated sugar
1 tsp vanilla extract
12 oz (1 bag) chocolate chips
Preheat your oven to 400 F.
Beat the egg whites until you reach soft peaks. Slowly add in the vanilla extract and sugar, and beat until incorporated. Stir in the chocolate chips.
Plop fist-sized dollops of batter onto parchment-paper-covered cookie sheets. (The cookies don't expand, so they don't need to be too far apart.)
Put them in the oven. Turn the oven off immediately, and leave them in the off oven with the door closed for at least 4 hours.