Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.

In a saucepan over low heat or in a microwave-safe bowl, melt the unsalted butter and chopped unsweetened chocolate together. Stir until smooth. Remove from heat and let cool slightly for 5 minutes.

In a large mixing bowl, whisk together the cooled chocolate mixture and granulated sugar until well combined. The mixture should be thick and glossy.

Whisk in the eggs one at a time, incorporating each egg fully before adding the next. Stir in the vanilla extract. The mixture should become even glossier and slightly lighter in color.

In a separate medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking powder, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing with a rubber spatula until just combined. Be careful not to overmix.

Gently fold in the semi-sweet chocolate chips until evenly distributed.

Using a small cookie scoop (about 1.5-2 tablespoons), drop spoonfuls of dough onto the prepared baking sheets, leaving about 2 inches between each cookie.

Bake for 9-11 minutes, or until the edges are set but the centers still look slightly soft and fudgy. Do not overbake.

Remove from the oven and let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely. They will firm up as they cool.