For the apple filling

In a medium or large sized saucepan, combine apples, brown sugar, butter, cornstarch, cinnamon, and salt.

Heat over medium low heat. Stir frequently until butter is melted. Once butter is melted, increase heat to medium and bring mixture to a simmer. Simmer for 5 minutes, stirring frequently. Mixture should thicken slightly and apples should be tender when pierced with a fork when finished.

Remove mixture from heat and stir in vanilla extract. Pour into a heatproof bowl and allow mixture to cool while you prepare your crumble (you can place it in the fridge and stir occasionally to speed up the cooling process).

For the crumble

In a medium sized mixing bowl, combine oats, flour, sugar, baking soda, cinnamon, and salt.

Add butter to the flour mixture and use a fork to combine. Don’t over-mix, mixture should still be clumpy. Set aside while you prepare your batter.

For the crust

Preheat oven to 325F (165C).

In a medium sized bowl, combine graham cracker crumbs, finely chopped walnuts, and sugars.

Add melted butter to the mixture and stir until butter is well incorporated and all crumbs are moistened.

Press crust mixture evenly onto the bottom and up the sides of a 9-inch springform pan. Set aside.

For the cheesecake batter

In a large mixing bowl, use an electric mixer to combine cream cheese and sugar. Beat on medium-low speed until smooth, creamy, and free of lumps. Don’t over-beat or whip too much air into the batter, but do make sure batter is uniform and smooth. Scrape sides and bottom of the bowl periodically.

Add sour cream and vanilla extract and stir on low speed until combined.

Lightly beat one egg then add it to the cheesecake batter. Stir on low-speed until just combined. Repeat with remaining eggs. Scrape the sides and bottom of the bowl to ensure all ingredients are evenly combined.

Assembly

Pour about half of the cheesecake batter over prepared crust in springform pan.

Using a slotted spoon to drain excess juice, layer about half of the apple mix over the cheesecake batter. Pour the remaining cheesecake batter overtop. Top batter with remaining strained apples, then scatter crumble evenly overtop (if crumble has solidified as it’s been sitting, just break it up with your hands). Place pan on a foil lined baking pan and transfer to center rack of 325F (160C) oven. Bake for 60-70 minutes (dark-colored pans tend to take less time, and lighter-colored pans take longer). Cheesecake is finished when, if slightly jostled, the edges are mostly set but the center still gently jiggles like jell-o. Allow to cool to room temperature in a warm, draft-free place (you could use the top of your oven or, turn your oven off, crack the door several inches, and allow it to sit for about an hour before removing to room temperature to cool further).

Transfer to the refrigerator and chill for at least 6 hours, preferably overnight, before slicing and serving.