Preheat the oven to 160°C (320°F) and place the rack in the middle.
In a mixing bowl, combine the flour, cocoa powder, baking powder, baking soda, and salt. Mix until evenly blended.
In another bowl, add the eggs, brown sugar, instant espresso powder, and vanilla extract. Whisk until smooth.
n a microwave-safe glass container, add the chopped dark chocolate and unsalted butter. Microwave for 1–2 minutes until most of it has melted. Stir with a spatula until the mixture becomes smooth and glossy.
Pour the melted chocolate mixture into the wet ingredients and mix thoroughly. Then add the dry ingredients and fold with a spatula until just combined. Let the batter rest at room temperature for 10 minutes.
Prepare two shallow dishes — one filled with granulated sugar and the other with icing sugar. Scoop a small portion of dough into the granulated sugar, coat it completely, roll into a ball, then coat it again in icing sugar.
Line a baking tray with parchment paper. Place the sugar-coated dough balls onto the tray, leaving generous space between them.
Bake in the preheated oven for 10–12 minutes, until the edges are set but the centers feel very light and soft when gently touched. Allow the cookies to cool completely on the tray before enjoying.
Using Dutch-processed (alkalized) cocoa powder results in a darker color, richer flavor, and a more tender, moist texture. Compared with natural cocoa powder, which is more acidic, Dutch-processed cocoa has a more neutral pH. This means the baking soda and baking powder produce slightly less gas during baking, preventing the cookies from becoming overly airy or porous and reducing moisture loss. Dutch-processed cocoa also typically has a higher fat content, contributing extra moisture retention.
Egg size will affect the total liquid content and therefore the texture of the dough. If the dough feels too loose or runny after mixing, add 10–20 g of flour to adjust. After resting for 10 minutes, the dough should hold its shape and not spread on its own.
Baking time depends on your oven’s actual temperature, the baking tray material, and the size of each cookie. Around the 10-minute mark, open the oven to check the texture. When the edges feel firm but the center is still soft and airy, the cookies are done. Over-baking will make the interior dry and crumbly.
YouTube