Measure out the rice cereal and set aside. In a large 4 qt or larger pot, add the butter, vanilla, and marshmallows. Cook on medium to low heat and stir often until the marshmallows melt completely.
Once the marshmallows have melted, add in the rice cereal and stir really well. Ensuring everything is evenly coated. In an 7x7 or 8x8 inch size dish, line with parchment paper.
Add the mix into the dish and press the mixture around to ensure it is even and level. Don't push too hard! otherwise the treats will be hard to bite through. I find just a little pressure to even things out is perfect.
Set the mix aside to cool and form to the dish. You can place it in the fridge for up to 30 minutes if needed.
In a medium sized microwave safe bowl, add in white chocolate chips and oil. Microwave for 1 minute, stir mix and then microwave for another minute. Everything should be melty and smooth.
Dip the krispies into the melted chocolate, gently shake off any excess chocolate. Place the krispies on a parchment paper and sprinkle with holiday sprinkles. Let them cool in the fridge or in a cool place, enjoy!