Place a metal loaf pan in the freezer 15 minutes before making ice cream.
Melt the chocolate in the microwave for 1 minute in 30 second intervals stirring vigorously after each. If you need more time to melt the chocolate, place it in the microwave in 15 seconds increments. Each microwave is different so watch the chocolate. If it heats too fast or long it will burn on the bottom. Beat until smooth. Cool and set aside.
Place the 20 marshmallows on a cooking sheet and place under the broiler for about 1 1/2 minutes. When brown and toasted on top, flip the marshmallows over. I used another small cookie sheet and flipped them upside down. Brown the other side. It only takes about one minute.
Once the marshmallows have charred on both sides, take them out of the oven to cool.
Make Chocolate shavings by grating, using a peeler or chopping with a knife.
Cut four rectangles of graham crackers on the perforated marks. Cut each into smaller piece until all pieces are about 1/2 inch.
Pour the contents of the Sweetened Condensed Milk in a large bowl.
Mix in the melted chocolate until smooth.
Place the heavy cream into a large bowl and add the cocoa powder. Whip on low until the cocoa is mixed in. Turn the mixer to a higher level and beat until it has very stiff peaks, almost butter, but not quite.
Fold in half of the whipped cream to the SCM mixture. Mix until almost smooth, but not quite.
Pull apart the cooled marshmallows and put 10 of them in the whip cream SCM mixture. Mix and pull the marshmallows apart as you mix.
Pour in the other half of the chocolate whipped cream and fold into the SCM mixture. When it is almost smooth, but not quite. Add the other 10 toasted marshmallows. Pull them apart and add to the SCM mixture.
Add in the graham crackers, chocolate shavings and the other half cup of small marshmallows. Fold everything together.
Pour into the frozen loaf pan. Cover with the plastic wrap
Freeze for 4 hours or overnight.