Melt the butter and 8 ounces chopped chocolate in the microwave at 50% power in 30 second intervals. Stir until smooth and set aside to cool a bit.

Place the eggs and sugar in the bowl of a standing mixer (or use a hand mixer). Using the whip attachment, beat on high for 3 minutes, until pale and fluffy.

With the mixer on low speed, pour the chocolate mixture into the eggs and mix to combine.

Whisk the dry ingredients together. Add to the chocolate mixture and mix on low until partially combined. Dump the chopped chocolate or chocolate chips into the bowl and finish mixing by hand, gently folding until no streaks of flour remain and the chocolate is evenly distributed.

Chill for at least 2 hours, or preferably overnight (note: the cookies bake well after 2 hours but better after overnight).

When you are ready to bake, preheat the oven to 350 F. Line a baking sheet with parchment paper or silicone. Scoops balls of dough about 2 tablespoons in size--I baked them 6 cookies to a sheet. Sprinkle with sea salt and cacao nibs.

Bake for 17-20 minutes; the cookies will still be soft in the middle but should be firm at the edges (the cacao nibs will be dark brown). Let cool on the pans for 5 minutes and then transfer to a cooling rack. These cookies are best eaten the same day they are baked, and preferably warm, but they will keep for 2-3 days. The dough will keep in the fridge for up to 3 days, so I recommend not baking them all at once (unless you need them all of course).