Strawberry lemon cheesecake

Ingredients

• a little sunflower oil, for greasing
• 300g digestive biscuits
• 100g unsalted butter, melted
• 2 x 250g tubs mascarpone
• 200g caster sugar
• 4 tsp cornflour
• 3 large eggs, beaten
• 2 x 300ml cartons soured cream
• finely grated zest of 1 lemon
• 2 tbsp lemon juice
• 1 x 300g punnet strawberries, hulled and chopped
• 3 tbsp caster sugar
• 11⁄2 tbsp lemon juice, or to taste
• 1 x 300g punnet strawberries, hulled and sliced
• 2 tbsp icing sugar
• a few shredded mint leaves, to serve