In a saucepan, melt the chocolate by stirring it over low heat until smooth and melted.
Add the vanilla extract.
In a separate bowl, mix the flour, sugar, baking powder, baking soda and salt, stirring well.
Pour the chocolate mixture into the dry mixture and stir. Stir in the butter, milk and eggs, beating until smooth.
Transfer the batter to a cake pan and bake it in a 350 degree F. preheated oven for about 30-40 minutes, or until a toothpick inserted in the center of the cake comes out clean.
This is a very simple and all purpose chocolate cake. Just stir the batter and throw into the oven and you'll soon be eating cake.