In a large saucepan, melt butter.
Add in marshmallows and stir continuously until fully melted and mixed with the butter.
Remove from heat and fold in rice krispies.
Dish into a 9 x 13 in baking pan.
Wet hands and evenly press mix into the pan.
Pour M&M’s® out on top of the pressed treats and use a paper towel to gently press them into the treats.
Let set for 15-20 minutes before cutting.
Once cut, melt chocolate in a wide-bottom microwave safe bowl in the microwave for 30 second intervals, stirring in between each one until melted.
Dip the bottom of the cut marshmallows in the chocolate and set on wax paper to set.