01 -
Lightly grease a 23 x 33 cm rectangular pan with cooking spray or line with parchment paper and set aside.
02 -
Place sugar cookie mix in a microwave-safe bowl and heat in 30-second intervals, stirring between each, until it reaches 71°C.
03 -
In a large pot set over low heat, melt the butter until fully liquefied.
04 -
Add large marshmallows to the melted butter and stir continuously over low heat until smooth and fully melted.
05 -
Stir in the heat-treated sugar cookie mix and vanilla extract until evenly combined, then remove the pot from the heat.
06 -
Gently fold in rice cereal, mini marshmallows, and 20 g of holiday sprinkles until the mixture is evenly coated.
07 -
Transfer the mixture into the prepared pan and, using a greased spatula, press down gently until level and compact.
08 -
Sprinkle the remaining 10 g of holiday sprinkles over the surface and allow the slab to set at room temperature for 30 minutes.
09 -
Cut the set mixture into squares of desired size and serve.