1 cup butter, softened
1/2 cup brown sugar
3 eggs
1 teaspoon vanilla extract
1 1/2 cups all-purpose flour
1/4 teaspoon salt
3 tablespoons unsweetened cocoa powder
2 teaspoons baking powder
1/2 teaspoon baking soda
1 1/2 cups chocolate chips
Preheat oven to 375 degrees F (190 degrees C).
In a medium bowl, cream together the butter, brown sugar and brown sugar until smooth. Beat in the eggs, one at a time, then stir in the vanilla and cocoa. Combine the flour, salt, cocoa, baking powder, baking soda and chocolate chips; gradually pour into the creamed mixture. Mix until well blended. Drop by rounded spoonfuls onto ungreased cookie sheets.
Bake for 1 hour in the preheated oven, or until cookie edges are lightly browned. Cool on baking sheet for 2 minutes before removing to a wire rack to cool completely.