In a medium bowl, whisk together the Dutch cocoa powder, granulated sugar, vegetable oil, and espresso powder until glossy and well combined. Beat in the eggs one at a time, followed by the pure vanilla extract. Whisk vigorously for 1 minute until completely smooth.

Stir in the all-purpose flour, baking powder, and fine sea salt with a rubber spatula just until combined and no dry streaks remain. Fold in chocolate chips if using. The dough will resemble a thick, sticky brownie batter. Cover the bowl tightly with plastic wrap and chill in the refrigerator for at least 2 hours (or overnight) until very firm and scoopable.

Preheat your oven to 350°F (175°C) and line two large baking sheets with parchment paper. Place granulated sugar into one small bowl and powdered sugar into a second bowl. Scoop rounded 1.5-tablespoon balls of chilled dough. Roll first into granulated sugar to create a moisture barrier, then roll thoroughly in the powdered sugar until heavily and completely white.

Place sugar-coated dough balls onto the prepared baking sheets spaced 2 inches apart. Bake at 350°F (175°C) for exactly 9 to 11 minutes until the cookies have puffed, spreading into dramatic cracked crevices while the centers remain soft and fudgy. Do not overbake!

Let cookies rest on the baking sheet for 5 minutes (they will settle and finish setting their gooey centers), then transfer to a wire cooling rack to cool completely. Serve with a cold glass of milk or hot cocoa!