Begin by filling a small pot with ½ cup of water and place it over medium heat to create steam for the Bain-Marie method.

Once the water is boiling, reduce the heat to low and place the heatproof bowl on top of the pot. Add the unsalted butter and marshmallows, whisking continuously for 2–4 minutes until smooth.

Lift the bowl off the pot, sprinkle in salt and add red food coloring, whisking to combine.

In a large mixing bowl, pour the Rice Bubbles and pour the melted marshmallow mixture over them, mixing vigorously until coated.

Grease hands with butter and shape the mixture into oval 'brain' shapes, pressing a dent in each for realism.

Using a toothpick dipped in red food coloring, create vein-like patterns on the brains, then let cool completely before storing.