How to Make a Christmas Botanical Yule Log

Heat the oven to 120°C, fan 100°C, gas ½.

Line 2 baking trays with baking paper. Using an electric whisk, beat the egg whites in a clean bowl. Start with a low speed, increasing to high. Whisk for 3-4 minutes until you have a stiff meringue. Add the sugar 1 tablespoon at a time, whisking in between additions until all the sugar is incorporated.

Rub a little meringue between your fingers to make sure no sugar grains remain.

Spoon your meringue mix into a large piping bag with a round nozzle 1cm wide. Use half the meringue mix to pipe 8 mushroom tops – a range of small and medium rounds about 3-5cm wide, 2cm high – onto the baking trays, a couple of inches apart (use a wet finger to press down any peaks). Pipe 10 bases 1-2cm wide and 3cm-6cm long.

Transfer to the oven to bake for 1 hour. When the meringues are ready, they will pull off the paper easily – if not, pop them into the oven for a few more minutes.

Cool for 1 hour; peel off the paper.

Melt the dark chocolate in a heatproof bowl over a pan of barely simmering water; don't allow the bowl to touch the water.

Use a teaspoon to dollop chocolate into the middle of each upturned mushroom top. Press a base onto each mushroom top and dust with cocoa powder then leave to set at room temperature.

Spoon the mixture into the lined tray, gently and evenly spread it to the edges of the tin and give the tin a few sharp taps on a flat surface to disperse any air bubbles.

Bake for 8-10 mins, or until it is cooked through evenly and springy to touch.

While the mixture is still warm and flexible, turn the sponge out top down onto the sugared paper. Peel off the first baking paper and discard.

Leave to cool.

For the caramel filling, combine granulated sugar and salt (bag 4) with 50ml water in a saucepan. Stir over a medium heat until the sugar has dissolved, then simmer for 5 minutes, continuing to stir until it becomes a golden colour.

Top Tip: Watch this closely as it can easily burn.

Remove the caramel from the heat and then immediately add in the 50ml of cream and stir well until it has all combined. If lumps form, just keep stirring - the caramel should be a creamy colour and quite runny.

Transfer to a bowl and then cool completely at room temperature.

Start to tightly roll the sponge from the shortest side inwards, using the baking paper to help with the rolling.

Chill in the fridge for a further 15 minutes.

For the frosting, put the dark chocolate (bag 5) into a heatproof bowl. Heat 125ml of cream in a pan until it just begins to boil, then pour it over the chocolate. Stir with a wooden spoon until the chocolate has melted and the frosting is thick enough to spread.

Cool in the fridge for around 10-15 minutes.