Triple-chocolate rice krispie treats

Line the pan with parchment, using a little oil so the parchment sticks, and grease the parchment with the residue on the butter wrapper. Save the wrapper.

Melt the butter in the stock pot over low heat. Everything happens on low heat.

Chop the unsweetened chocolate so it melts more quickly.

Add the marshmallows to the melted butter and stir as they melt.

Chop the semi-sweet chocolate disks, leaving some pieces irregular and large.

When the marshmallows are melted, stir in a pinch of kosher salt and the vanilla extract until perfectly smooth and homogeneous.

Turn the heat down to warm and stir in the unsweetened chocolate until melted.

Kill the heat, add the rice cereal and stir until evenly coated.

Fold in the reserved marshmallows while still warm so they only partly melt, then the cacao nibs, then the semi-sweet chocolate and a good healthy pinch of flaky salt.

Transfer to the prepared pan and compress firmly with the butter wrapper into an even, tightly packed layer.

Leave to cool and set until very firm, about half an hour; the fridge speeds it up.

Turn out onto a cutting board and cut three by three into cubes.