Cherry and gingerbread bombe Alaska

1.Preheat oven to 160°C fan-forced. Grease and line base and sides of a 25cm square cake tin with baking paper.

2.For gingerbread, stir butter, sugar and treacle in a saucepan over medium heat until combined (5 minutes), then cool to room temperature. Sift flour and spices into a large bowl. Gradually stir in treacle mixture until just combined (do not overwork). Fold through eggs then ginger; set aside.

3.Warm milk in a small saucepan over medium heat. Remove pan from heat, stir in bicarbonate of soda and leave mixture to foam (5 minutes). Stir into batter then spread evenly in prepared cake tin. Bake until gingerbread is slightly risen, has a spongy feel and a skewer inserted comes out clean (50 minutes); cool in tin for 15 minutes. Turn out onto a wire rack to cool completely, then cut horizontally into four 1cm-thick layers. Use any remaining cake to fill any cake gaps in the bowl.

4.Grease and line a 9cm-deep, 17cm round ceramic soup bowl (900ml capacity) with plastic wrap, then spray with oil. Using the bottom cake layer, line the inside of the bowl, pressing cake to the side and trimming any excess cake flush with the rim of the bowl. Place in the freezer to firm (20 minutes). Using another cake layer, cut a 17cm round (the same size as the top of the bowl); this will be the base. Set aside to top once filled.

5.For cherry sorbet, stir 60ml water, sugar and glucose in a saucepan over medium heat until sugar dissolves (2 minutes). Add cherries, cook until softened (8 minutes), then cool to room temperature. Place cherry mixture, lemon juice and kirsch in a blender and blend until smooth. Transfer mixture to a bowl, placed over an ice-water bath and stir to cool completely. Churn mixture in an ice-cream machine, then spoon into the lined mould to half fill and freeze until firm (1 hour).

6.For cherry semifreddo, stir cherries, 60ml water and sugar in a saucepan over medium heat until sugar dissolves (8 minutes). Remove from heat and cool slightly. Transfer to a blender with kirsch and blend until smooth. Place in a bowl and cool completely in the fridge. Meanwhile, whisk cream and condensed milk in the bowl of an electric mixer on medium-high speed to soft peaks. Fold through cherry mixture then pour into mould to create a second layer. Top with gingerbread round, cover with plastic wrap and freeze overnight or until firm.

7.For Italian meringue, stir 80ml water, sugar and glucose in a small saucepan over medium heat until syrup reaches 114°C on a sugar thermometer (soft-ball stage; 10-15 minutes). A few minutes before sugar syrup is ready, whisk egg whites with cream of tartar in an electric mixer on medium speed to soft peaks. Increase speed to high and, with motor running, slowly add hot syrup. Reduce speed to medium and continue to beat until meringue is cooler and very thick (15 minutes). Swap the whisk for the paddle attachment, then continue to beat until cooled and glossy (10 minutes).

8.To serve, unmould bombe onto a cake stand. Cover with Italian meringue and use an offset spatula to create swirls. Scorch with a blowtorch until burnished.