Line 8x8 square pan with wax paper.
In a large pot, add butter and pinch of salt, then set to medium heat.
Once butter is completely melted, add 10 oz bag of marshmallows and vanilla extract. Stir until marshmallows are melted.
Turn off heat, then add rice crispy cereal, crushed Oreos, and additional marshmallows and mix until well combined.
Pour mixture into lined baking dish, then press down with your hands. Top with additional crushed Oreos and gently press into the mixture.
Once the mixture has cooled completely and is set, cut into squares and enjoy!