In a medium bowl whisk together flour, baking powder, and salt; set aside.
In a microwave-safe bowl add the unsweetened chocolate, bittersweet chocolate, and butter pieces. Heat in the microwave on 50% power for 1 minute. Stir and then heat on 50% power for 30 seconds, Stir and repeat until the chocolate is melted and glossy.
Add eggs and sugar to the bowl of a stand mixer fitted with a paddle attachment and beat on medium-high speed until thick and pale in color, about 3-4 minutes.
Pour in vanilla and beat on low for 10 seconds.
Scrape the chocolate mixture into the egg mixture and beat on low until combined, about 30 seconds, scraping down the sides of the bowl as needed.
Take the mixing bowl off of the stand mixer, pour in the flour mixture and chocolate chips, and fold into the batter until no white streaks remain.
Cover the bowl with plastic wrap and let it sit on the counter for 25-30 minutes. This will allow the batter to firm up (it will look like thick brownie batter).
While the batter firms up, move the oven racks to the upper-middle and lower-middle positions and preheat to 350 degrees F. Line 2 baking sheets with silicone baking mats or parchment paper.
Use a 1.5-Tablespoon scoop to scoop the cookies onto the prepared baking sheets, spacing the dough 2 inches apart.
Bake for 11-14 minutes, or until the cookies are cracked on top and shiny, rotating the pans halfway through baking.
Move the cookie sheets to wire cooling racks to cool completely before removing them from the baking sheets.