Measure exactly 10 cups cereal and add to a large bowl. Set aside.
Line a 13 x 9" baking pan lined with aluminum foil. Then sprayed. Set aside.
Melt butter over low heat in a large pot. Once butter is melted. Add all but 2 CUPS Marshmallows. Vanilla , salt.cook over Low heat until completely melted. Once mixture is smooth. Add remaining 2 cups Marshmallows and stir just until incorporated. ( Marshmallows will mostly melt but those lumps that are left are going to add little pockets).
Immediately pour marshmallows mixture over rice cereal and gently stir. Until cereal is evenly coated.press into pan . Allow to cool. Cut in squares.
