Preheat oven to whatever temperature the cookie dough package says.
Line a 11x7 baking dish with parchment paper with 2-inch overhangs on either side.
Press the cookie dough into the bottom of the baking dish in an even layer.
Bake for however long the cookie dough package says.
When the cookie layer is done baking, immediately pour bag of marshmallows on top of the cookie layer then put back in the oven for 5-7 minutes, until the marshmallows soften and become slightly melted (this could be less than 5-7 minutes). Remove from oven and set aside.
In the meantime, in a large, non-stick pot over medium high heat, melt butterscotch chips, butter, corn syrup, and vanilla extract together. Once the butterscotch chips have all melted and the mixture is smooth, turn off the heat and stir in the rice cereal. Stir until rice cereal is completely and evenly coated with the butterscotch mixture.
Place the butterscotch rice krispy layer evenly on top of the marshmallow layer and gently press down to flatten. You'll probably have to do this in parts as the rice krispy layer doesn't "spread."