*Pre-measure all ingredients and have them ready before starting. Grease or prepare a 9x13" baking pan by spraying it with nonstick cooking spray.
For the rice krispies base, in a large pan over medium-low heat, melt butter. Add marshmallows and stir constantly over the heat until they're all the way melted. Stir in 1 1/2 tsp. vanilla and 1/2 c. carrot cake mix until smooth. Working quickly, add crispy rice cereal and stir to fully incorporate the melted marshmallow mixture throughout. Press into prepared pan and let set.
Prepare the frosting by mixing together cream cheese, vanilla and powdered sugar in the bowl of an electric mixer until smooth and creamy. Add 1/4 c. carrot cake mix and mix until completely combined and creamy. Spread over treats. Let the frosting set for a bit, then slice into squares and serve.