Prep. Preheat the oven to 350˚F. Line two baking sheets with parchment paper.
Melt the chocolate. Add chopped chocolate to a heat-proof bowl with the butter. Set the bowl over simmering water in a pot. Make sure the water is not touching the bowl. Allow the chocolate to melt, stirring a few times until all is nicely smooth and runny.
Beat the eggs. To a separate mixing bowl,add the eggs, caster sugar, and brown sugar. Beat with a hand-held or stand mixer until fluffy. The goal is to dissolve the sugar as much as possible.
Add the chocolate. Remove the melted chocolate from the heat and let it stand for a few minutes to cool slightly. Do not add warm chocolate to the eggs, or the eggs will curdle. Gradually stir the chocolate into the eggs until well combined. Then, stir in the vanilla.
Fold the dry ingredients. Sift the flour, cacao powder, baking powder, and salt into the chocolate mixture. Stir until just combined. Finally, fold in the chocolate chips.
Bake the cookies. Drop around 2 tablespoons of the cookie dough onto the baking sheet. Make sure to leave 2 inches of space in between. Bake the cookies for 11 to 13 minutes, or until the edges begin to firm up but the centers still appear soft.
Cool, then serve. Remove the cookies from the oven and let them cool for 4 minutes on the baking sheet before transferring them to a wire rack to cool completely.
Notes
Because the cookie dough is fudgy, I suggest coating your scoop with some cooking spray to make scooping easier.
Please try to use quality chocolate with at least 60% cocoa.
You can sprinkle the cookies with sea salt flakes, if you like, when you pull the cookies out of the oven.