01 -
Softened unsalted butter, 1 cup (used for cookies).
02 -
Sugar, granulated, 3/4 cup.
03 -
Dark brown sugar, 3/4 cup.
04 -
1 large egg.
05 -
All-purpose flour, 1 2/3 cups.
06 -
Unsweetened cocoa, 2/3 cup.
07 -
Salt, 1 teaspoon.
08 -
Baking soda, 1/2 teaspoon.
09 -
More softened butter (3/4 cup) for the filling.
10 -
Powdered sugar (confectioners'), 2 cups.
11 -
Milk, 1 tablespoon.
12 -
Vanilla extract, 1/2 teaspoon.
13 -
Kosher salt, 1/2 teaspoon (used in filling).