• Preheat the oven to 170C/340F. Grease a loaf pan and line with baking parchment.
• In a large bowl, cream the butter and sugar together with an electric whisk until light and fluffy. And the eggs, one at a time, and beat each one in well. Mix in the grated celeriac and apple and then sift in the flour and salt and combine.
• Pour the mixture into the prepared loaf tin and bake for about 60 mins or until an inserted skewer comes out clean. If the cake is browning too quickly, cover it with foil loosely.
• Cool the cake in the tin for 15 minutes and then remove from the tin and allow to cool completely.

For the apple ice cream:

• Heat the sliced apples with a tablespoon of water in a saucepan over a medium-low heat until soft. Allow to cool slightly and puree with a hand blender or food processor until smooth. In a large bowl, whisk the cooled apple puree and cream, then sift in the sugar and whisk until combined. Chill in the fridge for at least half an hour. Churn in an ice cream maker for about 20 minutes, or until thickened, according to manufacturers instructions. Pour into a dish and freeze until firm.
• To freeze it without an ice cream machine, pour it into a large lidded container and stir every half hour for a few hours until firm. The final stir can be done with a hand blender to make it smoother.

For the butterscotch:

• Heat the butter and sugar in a saucepan over a medium heat, stirring gently until it bubbles. Add the bourbon and without stirring, boil the mixture for about 5-7 minutes until it is a deep golden colour. If necessary, scrape the sides down with a rubber spatula, but don’t stir.
• Remove from the heat and stir the cream into the sauce until combined. Be careful, it will bubble up considerably. Stir in the salt. Pour into sterilized jars and allow to cool.
• Slice the cooled cake thickly and heat on the griddle pan or barbecue until lightly charred. Top with a scoop of the ice cream and a drizzle of butterscotch sauce.