Preheat oven to 300 F. Line an 8x8-inch pan with parchment paper. Lightly grease the parchment paper.
In the bowl of a stand mixer fitted with a paddle attachment, beat together butter, sugar, and vanilla until well-combined.
Stir in flour and pretzel crumbs until just incorporated.
Press crust evenly into prepared pan.
Prick the crust with a fork all over the base.
Bake for 25-35 minutes, or until edges are golden brown and middle is light golden brown.
Remove crust from oven, and top with dollops of marshmallow fluff.
Let the fluff sit for 2-3 minutes to soften.
Gently spread the marshmallow over crust.
Sprinkle peanuts evenly over marshmallow fluff.
Let the marshmallow cool to room temperature.
Pour caramel evenly over peanuts.
Sprinkle cereal evenly over caramel.
Melt chocolate chips. I microwaved them in 30 second increments, stirring after each 30 seconds. It took about 2 minutes for them to melt.
Gently spoon melted chocolate over bars. Very gently spread as needed. If you spread the chocolate in one direction, it’s less likely to pull the cereal up.
Chill the bars for about 10-15 minutes, or until set, before slicing.