METHOD

1. Preheat oven to 160°C (325°F). Line a 24cm round springform tin with non-stick baking paper. Place the date, bicarbonate of soda, water and schnapps in a medium bowl and mash with a fork to combine. Transfer to a small food processor and process until well combined. 
   
2. Place the egg yolks, ¼ cup (45g) of the sugar and the orange rind in the bowl of an electric mixer and whisk on high speed for 7 minutes or until pale and thick. Add the date mixture and walnut meal and fold to combine. 
   
3. Place the eggwhites in a clean bowl of the electric mixer and whisk on high speed until stiff peaks form. Gradually add the remaining ½ cup (110g) sugar and whisk until thick. Scrape down the sides of the bowl and whisk for a further 2–3 minutes or until thick and glossy. Fold the eggwhite mixture into the date mixture in 2 batches. Pour into the tin. Bake for 1 hour 10 minutes – 1 hour 20 minutes or until just a few crumbs are attached when tested with a skewer. Allow to cool completely in the tin. 
   
4. To make the butterscotch toffee icing, place the sugar and water in a small saucepan over medium heat, stirring to dissolve the sugar. Increase the heat to high and bring to the boil. Cook, without stirring, for 7–8 minutes or until the temperature reaches 160°C (325°F) on a sugar (candy) thermometer+. Remove from the heat, add the butter, cream and schnapps and carefully stir to combine. Return to high heat and stir until smooth. Allow to cool at room temperature. 
5. Turn out the cake onto a cake stand or plate and spread with the icing to serve. Serves 8–10
   

+ You can find sugar (candy) thermometers at kitchen shops.