How to Make It
Preheat oven to 400°F. Cover baking sheet with a silicone baking mat or parchment paper. Place butter in a medium-size microwaveable bowl. Microwave on HIGH until butter melts, about 30 seconds. Cool slightly, about 5 minutes.
Add sugar, eggs, vanilla, and salt to melted butter; stir until completely smooth. Add flour; stir until smooth.
Spoon about 2 teaspoons batter onto prepared baking sheet; spread into a 3-inch circle. Repeat process twice to make a total of 3 circles. Bake in preheated oven until cookies brown around edges, 6 to 8 minutes.
Working quickly, loosen cookies from baking sheet with a spatula. Place small slips of paper with fortunes written on them in centers of cookies. Fold cookies in half over fortunes; press edges together to seal. Gently pull ends of cookies down over rim of a small bowl or jar; hold until set, 5 or 10 seconds. Repeat procedure 7 times with remaining batter to create 21 cookies.