Preheat oven to 350 degrees and line baking sheets with parchment paper.
In a small bowl melt 2/3 cup dark chocolate chips in the microwave on 50% power, 30 seconds at a time until smooth, set aside.
In a medium bowl cream butter, sugar, brown sugar together.
Add egg, vanilla extract, and melted chocolate and mix until smooth.
In another bowl whisk together the flour, cocoa powder, salt, and baking soda.
Add flour mixture to wet ingredients and stir to combine.
Fold in 1 cup dark chocolate chips.
Using a 3 TBS cookie scoop, scoop dough onto prepared cookie sheets 2 inches apart. Bake for 12-14 minutes, rotating halfway through.
Let cool on baking sheet for 5 minutes before transferring to wire rack.
Store in an airtight container for up to 1 week or freeze.