Preheat your oven to 160°C (fan). Lightly grease an 8 x 8-inch baking pan and line it with baking paper, leaving plenty of overhang to make it easier to lift out later. Blitz the digestive biscuits in a food processor or crush them in a food bag with a rolling pin until you have fine crumbs. Stir in the melted butter until the mixture looks like damp sand. Press this mixture firmly and evenly into the base of the prepared pan using the back of a spoon or cup. Place the pan in the fridge to chill while you make the filling. I like to line my pan with enough overhang so I can easily lift the bars out once they’re set.

In the bowl of an electric mixer, beat the softened cream cheese until smooth and fluffy. Add the white sugar, salt, and vanilla extract, mixing to combine. Add in the eggs one at a time, mixing well after each addition and scraping down the sides and bottom of the bowl to ensure an even batter. Pour the cheesecake batter over the chilled biscuit base and gently tap the baking tin on a sturdy surface to remove any air bubbles.

Place the peeled and diced Granny Smith apples into a large mixing bowl. Add the granulated sugar, grated lemon zest, ground cinnamon, and ground nutmeg. Stir well to combine everything and let the apple mixture sit for 5 minutes so the flavors can meld.

In another large mixing bowl, combine the cold, cubed unsalted butter with the all-purpose flour, cinnamon, demerara sugar, and granulated sugar. Using your fingertips, rub the butter into the dry ingredients until the mixture is sandy and resembles coarse breadcrumbs. This crumbly texture is what will give the topping its irresistible crunch.

Evenly spread the spiced apples from Step 3 over the cheesecake layer in the pan. Then sprinkle the crumble topping from Step 4 in an even layer over the apples. Place the pan in the preheated oven and bake for 45-50 minutes, or until the crumble is golden brown and the cheesecake filling is set. Remove from the oven and let cool completely at room temperature.

Once cooled, transfer the pan to the fridge and chill for at least 3 hours, or ideally overnight, to allow the cheesecake bars to set. When ready to serve, use the overhang of baking paper to gently lift the cheesecake from the pan. Drizzle with caramel sauce, slice into bars, and enjoy! For a little extra decadence, I like to use a salted caramel sauce.