Granini slice

Name: Granini slice
Prep time: 30 min
Cook time: 2 h 15 min
Total time: 2 h 15 min
Yield: 16 slices
Ingredients: butter; ¼ tsp bicarbonate of soda; ½ tsp cream of tartar; 20 g plain flour; 40 g cornflour; 2 eggs; 60 g caster sugar; ½ tsp natural vanilla extract; 1 tbsp water; 380 g orange juice; 50 g cornflour; 80 g white sugar; 1 egg; 600 g pouring (whipping) cream; 2 tsp gelatine powder; 60 g butter; 40 g orange liqueur; 250 g plain sweet biscuits; 100 g icing sugar; 30 g orange juice