2tablespoonsunsalted butter, plus additional to grease the pan
8cupsmini marshmallows, divided
6cupsfruity crisp rice cereal (or Fruity Pebbles)
Grease a 9×13 pan with butter.
In a large, deep pan (nonstick preferred), melt butter and 6 cups mini marshmallows over low heat until completely melted (no lumps of marshmallows remain).
Remove pan from heat and stir in fruity crisp rice cereal and 2 cups mini marshmallows. Continue to stir until all cereal and marshmallows are coated with marshmallow/butter combination. Pour into prepared pan.
Spray hands lightly with nonstick baking spray (or coat with butter) and press mixture gently into pan. Let cool completely before cutting into squares with a sharp knife.