Modified from Everyday with Rachael Ray
6 cups crispy-rice chocolate cereal
6 tbsp butter
1/2 tsp salt
2 tbsp cocoa powder
1 (4 oz) chocolate bar, chopped
1 bag (10.5 oz) plus 2 cups of mini marshmallows
Line a 9 by 13 inch pan with foil and spray with cooking spray. Melt butter in a large pot over high heat. Stir in cocoa powder. Add bag of marshmallows and salt. Stir with a silicone spatula until smooth. Remove from heat.
Add cereal and mix until distributed. Mix in rest of marshmallows and chopped chocolate, stirring until well mixed. Put into prepared pan. Cool for 2 hours before cutting into squares.