In a large saucepan, melt the butter over low heat. Once melted, add the mini marshmallows and stir continuously until completely melted and smooth.

Remove the saucepan from heat and stir in the vanilla extract and a pinch of salt.

Gradually add the Captain Crunch cereal to the melted marshmallow mixture, stirring gently until all the cereal is well coated.

Lightly grease a 9x13-inch baking dish with butter or cooking spray. Pour the mixture into the dish and press it down evenly with a spatula or your hands (damp hands work best to prevent sticking).

Allow the treats to cool at room temperature for about 30 minutes before cutting them into squares.