I made this for activity days and the girls really liked it.
Honestly I got this off the back of a brownie mix:)
1 Brownie mix
3 C marshmallows
1/2 C M&Ms
3/4 C Chocolate Frosting melted in microwave
1/3 C chopped walnuts optional (just add to brownie batter before baking)
Make brownie mix as directed. Pour into greased 9x13 pan and bake at 350 for 20 min remove and drop marshmallows on top and return to oven for 10 min more. When finished cooking pour M&Ms on top and drizzle with frosting. Cool completely before cutting.
Follow the boxes recipe for high altitude and cake like brownies.
Fold in 1/2 C sour cream. Jen B gave me this trick and it REALLY works well.