Begin by taking a large, thick pan and placing it over medium heat. Mountaineer butter, then add marshmallows and melt. Stir continually well they are melting.
Once melted, add your rice crispy cereal, vanilla extract, and a pinch of sea salt. Stir until your rice crispy cereal is completely covered in the marshmallow and butter mixture.
Lightly grease a 9 x 13 baking dish. Pour your prepared rice crispy mixture into the pan. Now, take a piece of wax paper, and press down on the top of your rice Krispies through the wax paper. This will allow you to smooth out the rice crispy treats in the pan, packing them together, without getting your hands all sticky.
If desired, add any toppings you wish to your packed rice crispy treats. Allow the rice crispy treats to set and cool off. Then serve and enjoy!