Lavender, granadilla & white-chocolate mousse cake with flower-studded honeycomb

For the marshmallow and white-chocolate mousse layer, place the chocolate and marshmallows in a bowl and melt in the microwave, 1 minute, stirring halfway through the melting time. Add the gelatine powder to the water and let it sponge, about 3 minutes. Place in the microwave and melt, 30 seconds. Do not let it boil. Add to the marshmallow mixture. Whisk the cream to soft peaks then carefully fold the cream into the chocolate and marshmallow mixture until smooth. Spray a 35cm x 14cm x 9cm oblong cake tin with cooking spray, pour the mousse layer into it and refrigerate to set, about 30 minutes.

For the granadilla mousse layer, add the gelatine powder to the first 60ml (¼ cup) water and let it sponge, about 3 minutes. Place in the microwave and melt, 30 seconds. Do not let it boil. Heat the strained granadilla pulp in a saucepan until hot, but do not let it boil. Add the melted gelatine, stir to combine and set aside at room temperature.

In the meantime, make an Italian meringue mixture for the granadilla mousse. Place the 120g castor sugar and second 60ml (¼ cup) water in a small saucepan and stir over low heat until dissolved. Bring to a boil and boil to soft-ball stage (116°C on a sugar thermometer). Brush the insides of the saucepan with a pastry brush dipped in water to prevent the sugar from crystallising. While the sugar is boiling, whisk the egg whites in a large bowl until soft peaks form. Add the lemon juice and continue to whisk to stiff peaks. Once the sugar syrup is at soft-ball stage, slowly pour it into the egg whites, whisking all the time. Continue to whisk until the meringue is glossy and stiff.

Using a metal spoon, fold the cooled granadilla mixture, fresh granadilla, 400ml double-thick cream and food colouring into the meringue. Pour on top of the set white-chocolate and marshmallow layer and refrigerate to set, about 30 minutes.

For the lavender mousse layer, blend the 300ml doublethick cream and cream cheese together until smooth, 2 minutes. Stir in the remaining ingredients and pour over the set granadilla layer. Refrigerate to set, 30 minutes.

For the honeycomb, gently heat the butter, 165g castor sugar and golden syrup in a mediumsized heavy-based pan until the sugar has dissolved. Turn up the heat and bring to a rapid boil, without stirring. Keep boiling until the mixture turns a goldenbrown colour and reaches 130°C on a sugar thermometer, about 5 minutes. Add the bicarbonate of soda and stir it for a few seconds. The mixture should expand. Tip the honeycomb onto a large 40cm x 32cm sheet of baking paper or a silicone mat and leave to cool, 1 second (it dries very quickly), then scatter the edible flowers randomly on top. Leave to cool and set completely. Break into shards.

To de-mould the mousse cake, pour some boiling water into a shallow baking tray large enough to fit the mousse tray. Dip the mousse tray into the hot water for 10 seconds. Run a blunt knife around the sides of the mousse – just enough to release the air. Invert your serving plate over the top of the mousse cake, then turn it over. Carefully release the mousse by lifting the tray. Decorate with honeycomb shards and edible flowers. Serve with fresh granadilla.