Preheat oven to 325°F (160°C). Grease a 9-inch springform pan and wrap the outside with aluminum foil if you plan to bake in a water bath.

Combine graham cracker crumbs and sugar in a bowl. Pour in the melted butter and stir until crumbs are evenly moistened.

Press mixture into the bottom of the springform and about 1/2 inch up the sides.

Bake the crust for 8–10 minutes, then remove and let cool while you prepare the filling.

In a skillet over medium heat, melt 2 tbsp butter. Add sliced apples, brown sugar, cinnamon, nutmeg, lemon juice, and a pinch of salt.

Cook, stirring occasionally, until apples are tender, about 6–8 minutes. Set aside to cool slightly.

In a large bowl, beat the cream cheese until smooth. Add sugar and beat until combined.

Add eggs one at a time, mixing gently after each.

Mix in vanilla, sour cream, and flour (if using) until the batter is silky and smooth.

Spoon half the cheesecake filling over the cooled crust and spread evenly.

Arrange half of the sautéed apples over the filling, then add the remaining filling on top.

Gently swirl with a spatula to create a marbled effect.

Scatter the remaining apples on top.

Place the springform pan inside a larger roasting pan. Pour hot water into the roasting pan until it reaches halfway up the outside of the springform.

Bake at 325°F (160°C) for 50–65 minutes until the center jiggles slightly.

Turn off the oven, crack the door, and let the cheesecake cool inside for 1 hour.

Then cool on the counter before refrigerating for at least 4 hours.

In a saucepan over medium heat, add 1 cup sugar and stir until it melts into an amber liquid.

Quickly add the cubed butter and stir until melted.

Slowly add warm heavy cream while stirring. Let boil for 1 minute, then stir in sea salt.

Cool to room temperature; caramel will thicken as it cools.

Unmold the chilled cheesecake, drizzle with caramel sauce, and garnish with flaky sea salt, toasted pecans, or apple slices. Slice with a hot knife.