Spray a 9 x 13 inch baking pan with non-stick cooking spray.

In a large pot, melt the butter over medium heat. Stir in the bag of big marshmallows and cook, stirring often, until marshmallows are melted. Add the pinch of salt, vanilla, and green food coloring and stir until the color is evenly distributed. Stir in Rice Krispy Treats and mini marshmallows. Stir until krispies are coated and mini marshmallows are just starting to melt.

Turn the mixture out into the prepared pan. Grease your fingers with cooking spray then press the mixture into an even layer. Allow to cool.

In a microwave safe container, melt the chocolate and butter in 30 second intervals until smooth.Stir in the peppermint extract. Dip one end of the Rice Krispies in the chocolate or spoon it over one side. Set on a parchment paper lined baking sheet. Sprinkle with sprinkles, if desired. Allow to set up for 1-2 hours, or until chocolate hardens.