Spray a 9x13 inch pan with cooking spray, set aside.

In a large pot, melt the butter slowly, over low heat. When the butter is almost melted, add all the mini marshmallows and salt. Cook on low, stirring frequently, until the marshmallows are completely melted.

Remove the pot from the heat and stir in vanilla extract. Next, add the Rice Krispies cereal and stir with a large spoon until all the marshmallows and Rice Krispies are completely combined.

Spread into the prepared 9x13 inch pan. Gently press with slightly damp fingertips. If you'd like, sprinkle on desired toppings, which can be mini chocolate chips, sprinkles, mini m&m's, or nothing at at all (they'll still be delicious). Enjoy!