Convert chocolate chip cookie recipe to chocolate chocolate chip cookie

Question

I have a really good chocolate chip cookie recipe. I'd like to convert this recipe to have a chocolate dough (ie make chocolate chocolate chip cookies). How can I convert it without losing the texture of chocolate chip cookies?

Here is the recipe, if that helps

2 1/2 cups flour
¾   cup sugar
¾   cup brown sugar
Tbs vanilla
tsp baking soda
pinch salt
2   eggs
1stick of margarine (more can be added for better taste)
½   cup chips (chocolate/vanilla)

Mix all ingredients except chocolate chips.
Add chips to dough
Make balls of EQUAL SIZE
Bake at 350 for about 12 minutes (or until they begin browning)
Let cool before eating

Answer 1

Replace 1-2 tbsp of the flour with cocoa powder, depending on how chocolatey you like your cookies.

Answer 2

You could melt another 1/4 cup of chocolate chips and add to the butter, eggs and sugar before incorporating the flour, which you might reduce by 1/8 of a cup or so.

Creaming the butter and sugar, then mixing in the eggs first will allow you to mix the flour and fold the chips in with minimal action which makes the cookies more tender...you want to mix the flour as little as possible so you don't develop the gluten and end up with tougher cookies.