In a medium bowl, combine dark hot chocolate, egg, and vanilla extract. In a separate bowl combine flour, cocoa, baking powder, and salt. Stir wet ingredients into dry until just mixed (do not overmix!).
Pour 1/4 cup of batter for each pancake into pan. Cook for 2 minutes, or until pancakes just begin to harden around edges. Flip and continue to cook for 2 minutes more.
To make the fudge sauce, combine chocolate chips and cream in a small saucepan over low heat. Whisk slowly until completely combined, then pour into gravy boat or cup with spout. Pour over pancakes and top with mini marshmallows!