Spray a 9x13 pan with nonstick cooking spray, or rub with butter. Measure out Rice Krispies; set aside.
In a large pot, melt butter and 5 cups mini marshmallows over medium-low heat.
When melted, remove from heat and immediately stir in cereal and remaining 2 cups mini marshmallows, until all cereal is coated with melted marshmallows. The mini marshmallows you add in will stay relatively whole.
Pour into prepared pan and press down lightly into an even layer. Let cool and cut into squares. For best taste and texture, serve the same day.
If desired, cover well and store at room temperature for up to 2 days.
Notes
Make sure to only press down lightly for the best texture! Spray your hands with nonstick spray, or use a piece of wax paper, or a butter wrapper to prevent the mixture from sticking to your hands.