Peanut Butter, Chocolate and Marshmallow Ribbon Fudge

Line a 23 cm x 32cm|9" x 13" baking tin with non-stick baking paper.

For the base: melt the chocolate and butter in a heatproof bowl over a pan of simmering (not boiling) water. Remove from the heat and stir in the peanut butter and rice krispies.

Spread the mixture evenly in the bottom of the tin and chill for 15 minutes.

For the peanut butter layer: melt the butter in a large heavy-based pan over a low heat. Add both the sugars, evaporated milk and salt. Increase the heat and slowly bring to a boil. Boil steadily for 7-10 minutes, until a little of the mixture can be rolled into a soft ball between your finger and thumb when dropped into cold water (115°C|238°F on a sugar thermometer).

Remove from the heat and stir in the marshmallow fluff. Stir until melted, then stir in the peanut butter and vanilla.

Spread evenly over the chilled chocolate base and chill.

For the white chocolate layer: put the sugar, evaporated milk, butter and salt in a large heavy-based pan over a low heat. Slowly bring to a boil, then boil for 5 minutes stirring constantly.

Remove from the heat and stir in the marshmallows until melted and smooth.

Add the white chocolate and vanilla. Stir until smooth and combined.