Have the fortunes (1x2-inch pieces of paper) ready to go.
Preheat oven to 325°F (163°C).
Prepare Baking Sheets & Muffin Tins
Line two baking sheets with silicone baking mats.
Lightly spray silicone mats and muffin tins with vegetable cooking spray.
Vegetable oil spray
Prepare Batter
Beat egg whites until frothy but not firm.
6 Egg whites
Whisk in melted butter, vanilla extract, and salt.
1/3 cup Butter, 1 teaspoon Vanilla extract, ¼ teaspoon Salt
Gradually add flour (and sugar if you want them sweeter) until completely combined with texture of runny pancake batter. Add more melted butter if batter is too thick.
1 cup Flour, white, all-purpose, 1/4 cup Sugar
Bake the Cookies
Spoon batter onto baking mats forming 4-inch wide circles, not too thick.
Start with just a few while learning how to fold them (next).
Bake until edges are slightly golden (approximately 3-5 minutes).
Shape the Cookies (1 Minute or Less)
Remove cookies from oven and immediately flip them over on the baking mat.
Place fortune in middle of circle and fold cookie over it to form a half moon shape.
Gently pinch the two corners and bring them together, then place cookie in muffin tin to help hold them in place.
Leave cookies in muffin tin on kitchen counter for an hour. They will become firmer but remain chewy.
Store in airtight container up to one week. Can also be frozen for 3 months.
Notes
Cooking Spray
I use cooking spray even though the silicone mat and muffin tin may already be stick-free because I found this batter tends to be clingy.
Shaping the Cookies
Do not worry if your cookies do not look like mine: have fun making them and come up with your own unique shapes.
They are already baked when you're shaping them, so thickness does not matter at that point.
Portions
You may not get 12 cookies from the basic recipe: it may be fewer or more depending on how thick you pour the batter.
Chocolate Options
Instead of adding fortunes insides, you could put a dollop of melted chocolate.