BAKED STRAWBERRY CHEESECAKE

80g unsalted butter, melted, plus extra for greasing • 200g digestive biscuits • FILLING: 650g full fat soft cheese, at room temperature • 200g ricotta, at room temperature • 150g soured cream, at room temperature • 4 tbsp cornflour • 200g caster sugar • 1 lemon, zest • 1 tsp vanilla extract • 4 eggs • TOPPING: 500g strawberries, hulled and halved • 30g caster sugar • 1 lemon, juice