Add your 8 oz. of semi-sweet chocolate to a microwave safe bowl. Melt the chocolate in 20-30 second increments until it's smooth, stirring thoroughly each time you take it out to check. Set aside.
In a large bowl, combine your softened butter with your brown and granulated white sugar. Beat with your mixer until creamy - about 1 minute. Add in your 2 room temperature eggs and your vanilla extract and beat until super smooth and creamy. To that mixture, add your melted chocolate. Mix until fully incorporated.
Using a sifter over the bowl, add in your flour, baking powder, cocoa powder, espresso powder and pinch of salt. Using your mixer one last time, mix these gently together on low speed (so you don't spill it everywhere!)
Once your dough is fully incorporated, gently fold in your chocolate chips using a rubber spatula. I did about 1/4 cup chocolate chips into the dough and then topped them with 1/4 cup chocolate chips once they were baked and warm.
Let your dough sit, uncovered, in the fridge for 45-60 minutes. About 15 minutes before you take your dough out of the fridge, preheat your oven to 350 degrees and line a couple of baking sheets with parchment paper of silicon.
Once your dough is ready, it will be a little bit hard. I suggest using a tablespoon to scoop it out (about 1.5-2 tbsp worth of dough) into your hands and then rolling them into large balls. Place on the cookie sheet - I was able to fit 8 on one cookie sheet.
Bake at 350 degrees for 11-12 minutes. The middles should still be slightly gooey. Once you've taken them out of the oven, let them cool on the pan for 10 minutes then move them onto a cooling rack. While still warm, place chocolate chips on the top of them, followed by a pinch of sea salt.
Eat while warm! These can keep up to 3-4 days in a sealed container at room temperature.
If you don't have room temperature eggs, place them in a bowl with lukewarm water for 15 minutes or so. This should do the trick!