Preheat oven to 350 degrees Fahrenheit. Line baking pan with parchment paper.

First, add softened butter, granulated sugar and brown sugar to the bowl of a stand mixer. Beat for 2 to 3 minutes or until no clumps of butter remain.

Then, add in the eggs and vanilla extract. Stir to combine.

Add in the flour, baking soda and sea salt. Stir until a thick dough is formed.

Fold in the chocolate chips.

Take half of the cookie dough and place it in another bowl. Add the cocoa powder to this half of the dough. Stir until a thick chocolate dough is formed.

Assemble the cookies. Take a spoonful of the regular cookie dough and a spoonful of the chocolate cookie dough. Use your hands to roll into a ball. Place on the pan. Repeat for the remaining dough.

Bake for 9 to 10 minutes or until cookies are barely set in the middle.

Finally, remove from oven. Cool on pan for 5 minutes before carefully transferring to a cooling rack.