Preheat the oven to 180°C (160°C fan bake). Line a 28 x 18cm slice tin with baking paper.
To make the base, mix the melted butter, sugar and vanilla until well combined.
Sift in the flour and cornflour and stir until a soft dough forms.
Press evenly into the prepared slice tin and bake for 17–20 minutes or until golden.
Place the jam in a small bowl and stir vigorously until runny. Spread evenly over the warm shortbread base. Set aside.
To make the Pink Marshmallow, place the cold water in a large saucepan. Sprinkle the gelatine over the top and set aside for 5 minutes.
Add the sugar and lemon juice and stir over a low heat until the sugar has dissolved.
Bring to the boil, then continue to boil for 8 minutes without stirring.
Remove from the heat and leave to cool for about 20 minutes until lukewarm.
Add the icing sugar and vanilla or raspberry essence to the cooled mixture and beat with an electric beater for about 5 minutes until the marshmallow is very glossy and thick.
Add the food colouring a drop at a time until your desired pink colour is reached.
Carefully spread the marshmallow over the jam and biscuit base. Leave to sit at room temperature for about an hour until the marshmallow has set.
To make the Chocolate Topping, stir together the chocolate and oil in a medium heatproof or
microwave-safe bowl. Set the bowl over a pan of simmering water or heat in short bursts in a microwave, stirring between bursts, until completely melted and smooth.
Carefully spread the Chocolate Topping over the set marshmallow. Refrigerate for 1 hour or until the chocolate has set.
Use a hot knife (this will stop the chocolate from cracking) to cut the slice into 16 squares.
A Table at Tangleby
In this exceptional book, it shares more than 170 delicious dishes, from simple snacks to dinner parties that are guaranteed to impress your guests.