Melt the butter in a large, light-coloured saucepan over a low heat.
Sprinkle in a few pinches of fine sea salt and stir to dissolve.
Dump your marshmallows in and cook gently. Stir constantly, until they’ve all melted and are completely blended, with no lumps.
Take the pan off the heat and mix in your spelt and brown rice puffs immediately, making sure they’re all coated and glossy.
Wearing latex gloves, or coating your hands in a little melted butter to avoid your hands getting really sticky, press the mixture into a 9 x 9-inch square tin.
Leave to set, then cut into 12 crunchy squares.
Melt your chocolate in a glass bowl set over a saucepan of simmering water. Be careful to ensure the water doesn't touch the bottom of the bowl or you may end up with a grainy, hard chocolate instead.
Fill a piping bag with the melted white chocolate and snip off the end, then pipe lines across your cut bars to create mummy-like bandages.
Add two edible eyes to each bar and leave to set completely before serving.