Preheat your fan oven to 150°C (300°F) or 165°C if you're not using a fan oven. Line the bottom of a 18 cm (7 inch) springform pan with baking paper. Set aside.
Using a food processor ground your cookies. In a separate bowl, combine them with melted butter, cinnamon and granulated sugar using a spoon. Press the mixture into the bottom of the pan. Bake for 5-6 minutes then set aside to cool.
In a large bowl, using a hand mixer, mix together the cream cheese, sugar, vanilla extract and lemon juice until combined and smooth. Add one egg at the time, scraping the sides of the bowl to make sure everything is thoroughly combined. Set aside while you prepare the topping.
Peel and dice apples. You should have around 130 g of diced apple. If you put too much, the filling might not support the topping. In a small bowl, combine apples with sugar, cinnamon and nutmeg.
Make streusel topping by mixing together all-purpose flour, rolled oats, unsalted butter and sugar. Squeezing it with your hands, you should be able to form small clumps to scatter over apples.
Pour the filling over a cooled and baked cookie crust. Smooth it out with a small offset spatula. Sprinkle with prepared apples, then with streusel topping. You might not need all of it. Bake for 25-30 minutes in a preheated oven.
Once it's done, place the pan on a cooling rack and leave it to cool to room temperature. Then put the cheesecake in the fridge to cool completely, at least 4 hours.
Before serving, generously drizzle over caramel sauce. Enjoy!
for the salted caramel sauce
In a thick bottom saucepan combine sugar and water. Make sure every sugar granule is covered with water. Heat it up over medium to high heat, until it reaches golden amber colour. DO NOT STIR IT. This will take about 15 minutes.
While the sugar is dissolving, heat the heavy cream to a simmer. Once the sugar syrup reaches a desired colour, pour the heavy cream over it in a steady stream, stirring constantly with a silicone spatula. There will be a lot of bubbles and steam, be careful not to burn yourself.
Once all the bubbles have subsided, put the saucepan back on the stove and cook it for 1-2 minutes, stirring constantly. When it's done, put the caramel sauce in a clean jar and leave it to cool to room temperature.