In a large bowl, cream together the butter, brown sugar and white sugar until smooth. Mix in the eggs one at a time then stir in the vanilla.
Sift together the flour, cocoa powder and bicarb soda then stir into the butter mixture until well blended. Mix in the dark chocolate chips, milk chocolate chips and white chocolate chips so they are evenly distributed. Drop by heaping teaspoonfuls onto ungreased baking trays.
Bake for 6 to 8 minutes in the preheated oven, or until tops are no longer shiny.