Add butter, unsweetened chocolate and 1 cup of the chocolate chips to a double boiler. (A bowl set over a saucepan filled with warm water) Stir until chocolate and butter have melted. Takes a couple of minutes. Alternatively melt butter and chocolate in the microwave in 30 second intervals until melted.
Meanwhile, add eggs and both sugar to a stand mixer with the whisk attachment. Whip on high until mixture becomes thick and lighter in color, 2-3 minutes.
Slowly add in melted chocolate on low speed until combined.
Sift flour, baking powder and salt into a medium bowl.
Fold in the dry ingredients into the wet ingredients by hand. Fold in the remaining 1 cup of chocolate chips.
Refrigerate dough for an hour to firm up.
Preheat oven to 350 degrees.Scoop out heaping tablespoons of batter onto a silicone baking sheet.Bake for 10-12 minutes. (I like to under bake them slightly at 10 minutes)
Take out of the oven and allow them to cool for a couple of minutes on the sheet tray.Move to a cooling rack to cool completely.