There are tons of recipes for this online. I got this one from Kitchen Fun With My 3 Sons.
My niece Amy also made this with butterscotch chips and they are delicious.

Prepare a large cookie sheet by covering with parchment paper or wax paper,
Set aside.
Melt the white chocolate according to package directions.
In a large bowl, combine the melted white chocolate and peanut butter.
Stir until smooth.
Add the Rice Krispies, marshmallows, and half of the chocolate (butterscotch) chips.
Stir well.
Drop the mixture by heaping tablespoons onto the prepared cookie sheet and top with the remaining chocolate (butterscotch) chips.
Chill in the refrigerator until the cookies are set.