Preheat oven to 375*.
Butter a round or square pan, dust the sides and bottom with cocoa powder. Using a double boiler (or one pan over another pan with boiling water) 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, adding the eggs last, and mix well.
Pour the batter into the prepared 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.
Serve with vanilla ice cream and/or whipped cream.