Melt the chocolate chips and butter in a heavy saucepan or double boiler over low heat, or in the microwave until melted. Stir to combine.
Remove from heat, and set aside.
In a medium mixing bowl, whisk together the flour, cocoa powder, baking powder, and salt, and set aside.
In a large mixing bowl, beat the eggs, sugars, and vanilla on high speed 5 minutes, or until the batter is thick and creamy. Do not skip this step!
Reduce the speed to low, and mix in the melted chocolate..
Stir in flour mixture until just combined.
Fold in nuts, if using. (I don't like nuts in my brownies either)
Cover the batter, and chill for 30 minutes.
Preheat oven to 350 and line two baking sheets with parchment paper or a silicone baking mat.
Using a 3 tablespoon cookie scoop, drop batter onto the prepared cookie sheets about 2 inches apart.
Bake, rotating pans halfway through, for 15-18 minutes, until tops are shiny and crackly. The cookie will look set at the edges but still be a little wet looking in the center. Don't overbake, or the cookies won't fudgy.