1. Preheat oven to 180°C. Spray bottom and sides of a pan with cooking spray.
2. Melt butter. Put digestive biscuits into a bag and crumble with a rolling pin and then mix in the butter and egg and press into a pie dish or inch high baking tray and bake in the oven for 15 minutes.
3. Bake 15 minutes. Cool 10 minutes. Meanwhile, in another large bowl, beat cream cheese and sugar with mixer on medium speed until fluffy. Add whipping cream and eggs, beat on low speed until well blended.
4. Whip together the cream cheese, cream, 3 eggs, and caster sugar.
Spread the blueberries onto the biscuit base and then cover with the cream cheese mixture. Try and spread it all out evenly
5. Bake 40 to 45 minutes or until center is set. Cool 30 minutes. Refrigerate at least 2 hours before serving