Chocolate Brownie Crackle Cookies

0 Preheat oven to 350°F / 177°C.
1 Line sheet pans with parchment paper or a Silpat baking mat or spray them with nonstick cooking spray.
2 In a medium mixing bowl, whisk together flour, cocoa powder, baking soda, and salt. Set aside.
3 Using a standing mixer or hand mixer, beat butter until smooth. Add both sugars and continue to mix until light and fluffy, about 3 minutes. 
4 Add vanilla extract and eggs and mix on low until eggs are fully incorporated, stopping to scrape down the bowl as needed. 
5 Add dry ingredients to mixer and mix on low just until everything is combined. 
6 Pour powdered sugar into a shallow baking dish or bowl. 
7 Roll cookie dough into 1 1/2 inch balls (keep these small so the finished cookies are bite-sized) and then roll the balls in powdered sugar to fully coat. (You can do this in batches, dropping a bunch of the balls in powdered sugar and then rolling them all at once.)
8 Place cookie dough on prepared sheet pans, leaving a couple of inches of space between them. 
9 Bake until cookies are just barely set in the middle, 9-10 minutes. 
10 Allow cookies to cool on sheet pan for a few minutes before transferring to a cooling rack to finish cooling. 
11 Store in an airtight container at room temperature for up to 1 week.