Chocolate Wafers: Two Recipes

 Chocolate Wafers:

1 cup (130 grams) all purpose flour

1/2 cup (50 grams) unsweetened cocoa powder (regular or Dutch-processed)

1/4 teaspoon (1 gram) baking soda

1/4 teaspoon (1 gram) fine kosher salt

6 tablespoons (85 grams) unsalted butter, at room temperature

2/3 cup (140 grams) light brown sugar, firmly packed

1/2 cup (100 grams) granulated white sugar

1 teaspoon (4 grams) pure vanilla extract

1 large (30 grams) egg white, at room temperature

https://www.joyofbaking.com/ChocolateWafers.html

or these https://www.smells-like-home.com/2012/12/homemade-chocolate-wafer-cookies/