First, gather all of your ingredients and set the oven to 350 degrees.
Crush up the pretzels and mix with butter (melted) and sugar - layer along the bottom of a pan (either a 9x13 or a 9x9).
Mix cookie box according to direction and pour over the pretzel bottom.
Then layer the Reese's Peanut Butter Cups. I space them out quite a bit as to not create the deadliest of deadly...but you decided! Some say, the more the better!
Make the brownie mix and pour over the top of the whole dessert.
Bake in the oven - 350 degrees for about 40-50 minutes. Let it cool before you enjoy!
A little trick - we like to cut ours up into about 12 squares and individually put them in little snack bags and then freeze them - they're super good when frozen!