Best of both worlds with this apple pie and cheesecake in one pan. A spiced apple filling baked into the centre, finished with a brown butter oat crumble on top.
Peel, core and slice the apples into medium-thick slices.
Melt the butter in a saucepan over medium heat with the water, brown sugar, cinnamon, lemon juice, vanilla, nutmeg, cardamom and a pinch of salt, stirring until the sugar dissolves.
Add the apples and stir gently to coat without breaking them. Cover and cook on medium-low for 10 minutes, until fork-tender.
Stir in the cornstarch slurry and cook for another minute, until the juices thicken. Remove from the heat and let the filling cool completely.
For the crust, heat the oven to 180°C and line the base of a 25cm (10") springform pan with parchment.
Mix the biscuit crumbs, sugar, cinnamon and melted butter together until it looks like wet sand, then press firmly into the base of the pan. Bake for 8 to 10 minutes, then let cool to room temperature.
Reduce the oven to 150°C. For the cheesecake filling, beat the cream cheese, sugar and vanilla together until smooth and free of lumps.
Mix in the sour cream until fully incorporated.
Whisk the eggs lightly in a separate bowl, then add them to the batter and mix on low speed just until combined.
Mix in the cornstarch and fold it through gently with a spatula until smooth.
For the crumble, brown the butter over medium heat for 10 to 15 minutes, until it smells nutty and small flecks form, then remove from the heat and let it cool completely to room temperature.
Stir the flour, oats, brown sugar, cinnamon and salt together in a bowl, then pour in the cooled brown butter and mix with a fork until you have chunky crumbs.
To assemble, pour half the cheesecake batter over the cooled crust, then spoon over the cooled apple filling in an even layer.
Gently pour over the remaining cheesecake batter and smooth the top, then scatter the crumble generously over everything.
Bake at 150°C for 60 to 75 minutes, until the edges are set and the centre still has a slight jiggle.
Turn off the oven, crack the door open, and let the cheesecake cool inside for 1 to 2 hours — this slow cooling is what stops it cracking.
Once at room temperature, refrigerate for at least 5 hours, ideally overnight, to fully set.
Run a thin knife around the edge of the pan before releasing the springform sides.
Serve with caramel sauce, powdered sugar or just on it's own – perfect for autumn tea time.