Step one: mix up some chocolate muffin batter. Step two: double the chocolate chips and add half a cup of raisins, if you like. Step three: bake in a 9" or 10" square cake pan at 350 degrees F for about 30 minutes.
No need to let slip to anyone how healthy it is. Or how much work you save by dumping the batter into a cake pan instead of dividing it into muffins.