Wagon Wheels consist of two plain biscuits that are sandwiched with marshmallow and coated in chocolate. This version of the classic biscuit snack contains a layer of jam, too.
To make the biscuits, tip the flour, salt and butter into a bowl. Rub the butter into the flour until the mixture resembles fine crumbs. Stir in the sugar and vanilla paste, then add the egg yolk. Using your hands, bring the dough together. Wrap in cling film and chill for 30 minutes.
For the jam, place the raspberries in a small deep-sided pan and crush them with a wooden spoon. Add the sugar and bring to the boil over a low heat, until the sugar has melted. Increase the heat and boil for 4 minutes, until thickened. Remove from the heat and carefully pass through a sieve into a shallow container. Leave to cool and set.
For the marshmallow, pour 100ml of water into a small bowl, then sprinkle the gelatine over the top to soften. Set aside. Tip the sugar into a pan, add the glucose and 100ml of water and cook over a low heat to dissolve. Increase the heat and bring to the boil. Cook until the syrup reaches 120°C/248°F on a sugar thermometer.
While the syrup is cooking, whisk the egg white in the bowl of a stand mixer until firm but not dry. As soon as the syrup reaches 120°C/248°F, remove the pan from the heat and stir in the gelatine.
With the mixer on full speed, pour the sugar syrup over the egg white in a steady stream. Whisk for 5–8 minutes, until the mixture is thick and glossy. Whisk in the vanilla extract, then spoon the mixture into a medium piping bag fitted with a 1cm round nozzle.
Leave to cool to a perfect piping consistency – cool, but not completely set.
Heat the oven to 180°C/160°C fan/350°F/Gas 4. On a floured worktop, roll out the dough to 3mm thick. Cut out 16 circles with the 8cm cutter and place on the baking sheets. Freeze for 10 minutes, then bake for 10–12 minutes, until just golden. Remove from the oven, cool on the tray for 3–5 minutes, then transfer to a wire rack to cool completely.
To assemble, spread some of the melted chocolate over the bases of 8 biscuits. Leave to set. Pipe a layer of marshmallow over the remaining 8 biscuits.
Turn the chocolate-coated biscuits chocolate-side down. Spread the upper side with a layer of jam, then place a marshmallow-coated biscuit on top, marshmallow-side facing downwards.
Place the biscuits on a wire rack over a tray and pour the remaining melted chocolate over the top. Spread with a palette knife to create a smooth layer, spreading the chocolate around the edges until the biscuits are covered. Leave to set before serving.
Wagon Wheels is a registered trademark of Burton's Foods Ltd