In a large bowl, whisk together flour, sifted cocoa, and baking soda.

In a stand mixer fitted with the paddle attachment, beat butter on medium-low until smooth and creamy.

Add salt and mix for 15 to 20 seconds.

With mixer running on medium-low speed, pour in sugar and beat until fluffy, 2 to 3 minutes. Scrape down sides of bowl.

Add flour mixture in two additions, mixing on medium-low until incorporated, 15 to 30 seconds, before the second addition. Then mix until the dough forms.

On a work surface, use the palms of your hands and/or a dough scraper to form a 6x6-inch square of dough. Wrap in plastic and refrigerate for at least 1 hour.

Preheat oven to 325°F. Line two baking sheets with parchment or silicone baking mats.

Place half of the dough between two pieces of parchment and roll to 1/8-inch thick. If dough is soft, place in the refrigerator to firm.

Cut out cookies using a 1-inch cookie cutter and transfer to prepared baking sheets, placing the cookies about 1 inch apart.

Bake for 15 to 16 minutes, rotating the baking sheets from top to bottom and front to back halfway through, until fine cracks have appeared on the surface of the cookies.

Cool on baking sheets for 5 to 10 minutes, then transfer to a cooling rack.