Preheat oven to 350 degrees F (175 degrees C). Grease cookie sheets.
In a large bowl, cream together the butter, brown sugar and white
sugar until light and fluffy. Add the eggs one at a time, beating
well with each addition. Combine the cocoa, flour, and baking soda,
gradually stir into the creamed mixture. Finally, fold in white
chocolate chips. Drop by rounded spoonfuls onto the prepared cookie
sheets.
Bake for 8 to 10 minutes in the preheated oven, until puffy but
still soft. Allow cookies to cool on baking sheet for 5 minutes
before removing to a wire rack to cool completely.