01 -
Spray an 8x8-inch baking dish with nonstick cooking spray and set aside.
02 -
In a large pot over medium heat, melt the unsalted butter until fully liquefied.
03 -
Pour in the sweetened condensed milk and stir to combine. Bring to a gentle simmer, stirring constantly to avoid scorching.
04 -
Add the miniature marshmallows. Stir frequently until the marshmallows are fully melted and smooth.
05 -
Remove the pot from heat. Gently fold in the rice cereal with a rubber spatula until evenly coated.
06 -
Transfer the mixture into the prepared baking dish. Press mixture into an even layer with a spatula. Allow to cool at room temperature before cutting and serving.