01 -
Lay parchment paper in a 9x9 pan to stop sticking.
02 -
Heat the butter in a big pan on low. Toss in all but 1 cup of marshmallows and stir until smooth.
03 -
Take it off the heat. Mix in the vanilla, cereal, and leftover marshmallows until coated.
04 -
Use damp fingers to gently press into the pan. Wait an hour before cutting it up.