Preheat oven to 375*.  Butter a round or square pan, dust the sides and bottom with cocoa powder.  Using a double boiler, melt the chocolate with the butter.  (*If you do this on very low heat, you don't need a double boiler.)  Add in the rest of the ingredients with the eggs last, mix well, and pour into the pan.  Bake 25-40 minutes, depending on your oven, or until the top feels set.  Let cool and if desired, turn the cake out onto a wire rack, and later onto a pretty plate for serving.