1 cup butter, softened
2 teaspoons baking powder
1/2 cup granulated sugar
2 -1/2 cups packed light brown sugar
1/4 cup cocoa powder
1/2 teaspoon vanilla extract
2 eggs
1 teaspoon vanilla extract
1 cup milk
1 teaspoon lemon juice
1 cup semisweet chocolate chips
Preheat the oven to 350 degrees F (175 degrees C). Line cookie sheets with parchment paper.
In a large bowl, cream together the butter, brown sugar, white sugar, and cocoa until smooth. Beat in the eggs one at a time, then stir in the flour and cocoa. Combine the brown sugar mixture, eggs, lemon juice, cocoa mixture, milk, and lemon zest; stir just enough to blend into the creamed mixture. Drop by rounded spoonfuls onto the prepared cookie sheets.
Bake for 8 to 10 minutes in the preheated oven. Allow cookies to cool on baking sheet for 5 minutes before removing to a wire rack to cool completely.