Cream butter, cocoa, and sugars together in large mixing bowl.
Add egg and melted chocolate. Mix well.
Add flour and baking soda. Combine.
Press dough into bottom of sprayed or lined cookie sheet.
Bake for 7 minutes at 350 degrees.
Place marshmallows randomly on the cookie base.
Broil for 2 minutes.
Press the marshmallows down with the back of a spoon or spatula. Cool.
Melt the chocolate mint toppings together (dark chocolate chips, fresh mint, butter) and pour over the top of the broiled marshmall0ws. --I do this in a heavy saucepan on the oven but your microwave will work well, watch it closely.
Working quickly, use a spatula to spread the chocolate and melt it into the marshmallows.
Top with fresh mint, cool, and serve.