White Chocolate and Raspberry Tart

Name: White Chocolate and Raspberry Tart
Prep time: 30 min
Cook time: 3 h 20 min
Total time: 3 h 50 min
Cuisine: British
Ingredients: 250 g (2 ¼ cups) digestive biscuits, crushed; 120 g (½ cup + 1 tbsp) unsalted butter, melted; 190 g (1 ½ cups) raspberries (fresh or frozen), plus extra to decorate; 115 ml (½ cup) water; 1 tbsp cornflour (cornstarch); 2 tbsp caster sugar; 200 g (1 ½ cups + 1 tbsp) white chocolate; 70 ml (¼ cup + 1 tbsp) double cream; 30 g (2 tbsp + 1 tsp) unsalted butter