Add the butter and the marshmallows to a saucepan and heat over a medium to high heat, continuously stirring until it has all melted and is smooth.

Take it off the heat and add the Biscoff spread, stir until it is all combined.

Next, add the rice Krispies and mix until it is all well combined.

Place the mixture into a 20 cm square baking tin that has been lined with baking paper.

Use a spoon to flatten it down into the edges.

Melt the white chocolate in a heatproof bowl over a pan of simmering water.

Pour the chocolate over the Krispie base and spread all over.

Melt the Biscoff spread until it is runny, then drizzle all over.

Place in the fridge to set for 1-2 hours.

Cut into 12 pieces, then enjoy!