I created this recipe in the early 1980's after I had been on a trip & stayed at a Ramada Inn. I ordered Mississippi Mud Cake from the room service menu and fell in love! I decided to try to replicate that fantastic dessert & this is the result. It's not the same, but I think it's even better! It's very rich, so start with a small piece. Each ingredient represents a certain "ingredient" of the river. The fudge brownie = the muddy bottom; chocolate chips & pecans = rocks & pebbles; coconut = leaves & vegetation; marshmallow = white caps & foam; frosting = the muddy water; pretzels = driftwood.
Preheat oven to temperature recommended on package.
Lightly coat 9"x13" baking dish with cooking spray.
Prepare brownie mix batter according to package instructions; into the batter, mix chocolate chips, pecan pieces and coconut.
Bake according to package instructions (you may need to add up to 4 minutes for cooking time; toothpick test is not reliable due to the melted chocolate chips, use your best judgement.)
Remove from oven; allow to cool completely (approx. 1 1/2-2 hrs.)
Stir marshmallow cream with a knife or small off-set spatula; evenly spread marshmallow cream over top of cooled brownies.
Stir frosting; carefully spread frosting over marshmallow layer.
Sprinkle pretzel pieces, evenly, over frosting layer. (You may, also, sprinkle the pretzels over individual slices as they are served; the pretzels loose some of their crunch after it's been covered and refrigerated overnight.)
For ease of slicing, refrigerate for 1/2-1 hr. before serving.
Cover leftovers. May be left out at room temperature, but is best refrigerated.