Adjust an oven rack to the middle of the oven. Preheat the oven to 350F [180C]. Line three sheet pans with parchment paper.
In a small bowl, combine the flour, cocoa powder, baking soda, and salt.
In the bowl of a stand mixer fitted with a paddle, beat the butter on medium speed until creamy, about 1 minute. Add 1 3/4 cup [350 g] of the sugar, and beat again until light and fluffy, 2 to 3 minutes. Add the egg, yolk, and vanilla, and beat on low speed until combined. Add the flour mixture and beat again on low speed until just combined, then add the chopped chocolate and mix until incorporated.
Place the remaining 1/2 cup [100 g] of granulated sugar and cardamom in a medium bowl, and whisk to combine.
Scoop the dough into 1 1/2 oz [45 g] portions [2 tablespoons]. Roll each ball in the sugar until they are evenly coated. Place 8 cookies on each sheet pan.
Bake one pan at a time, rotating halfway through baking. Bake until the sides are set and the top begins to crackle, 12 to 14 minutes.
Transfer the sheet pan to a wire rack and let the cookies cool for 5 to 10 minutes on the pan, then remove the cookies and let them cool completely on the wire rack.
Store the cookies in an airtight container at room temperature for up to 3 days.