• In a bowl combine digestive crumbs, melted butter and light brown sugar until crumbs are moist. Press crumb mixture onto bottom and a little up the sides of a 20cm loose bottom or springform tin. Chill in fridge whilst preparing filling.
• Beat together mascarpone cheese, cream cheese, sugar, lemon juice in a bowl until smooth. Whip cream in bowl of stand mixer until stiff peaks form and then gently fold in cheese mixture. Pour filling onto biscuit crust and smooth over top with spatula. Cover and put in fridge to chill for 4 hours or overnight
• Dissolve 1 tablespoon of cornflour in 60 ml (¼ cup) of water and set aside
• Combine blueberries, 120 ml (½cup) water, lemon juice and sugar in a saucepan. 
• Cook over a medium heat for 2-3 minutes, stirring gently until sauce reaches a boil.
• Turn down the heat and add the cornflour mixture and stir gently until sauce thickens

To assembly

• Loosen edges of tin and press up from base removing cheesecake with a spatula. Spoon on top of cheesecake cooled blueberry mixture.