In a medium saucepan over medium heat, add 1 cup of granulated sugar. Stir continuously until it melts into a rich, amber liquid—about 10 minutes. Gradually whisk in 6 tablespoons of unsalted butter, followed by 1/2 cup of heavy cream, 1 teaspoon of salt, and 1 teaspoon of vanilla extract. Remove from heat, cool for 10 minutes, and set aside.

Preheat your oven to 325°F (163°C). Wrap the bottom of a 9-inch springform pan with aluminum foil, creating a seal. Place the pan in a larger roasting pan to prepare for baking.

In a food processor, pulse 1 1/2 cups of graham cracker crumbs with 6 tablespoons of melted unsalted butter, 1/4 cup of sugar, and 1 teaspoon of cinnamon until combined. Press mixture firmly into the bottom of the springform pan. Bake for 10 minutes until golden, then let cool.

In a large bowl, beat 16 ounces of softened cream cheese until creamy. Gradually add in 1 cup of granulated sugar and 2 tablespoons of cornstarch, mixing well. Then, blend in 1 cup of sour cream, 1 teaspoon of vanilla extract, 1 teaspoon of cinnamon, and 1/2 teaspoon each of nutmeg and allspice. Gently add 3 eggs, mixing until just combined.

Pour the cheesecake filling into the cooled crust. Place the pan in the preheated roasting pan and pour boiling water into the roasting pan until it reaches halfway up the sides of the cheesecake pan. Bake for 1 hour until the edges are set but the center is slightly jiggly. Turn off the oven and let cool in the oven with the door ajar.

After cooling, remove the cheesecake from the water bath and let cool on a wire rack for about 30 minutes. Cover with plastic wrap and refrigerate for at least 8 hours or overnight.

In a saucepan, add 3 cups of peeled and diced apples, 1/2 cup of brown sugar, 1 teaspoon of cinnamon, and 1 tablespoon of lemon juice. Cook over medium heat for about 8-10 minutes until apples are tender. Allow to cool completely before topping the cheesecake.

In a medium bowl, mix 1/2 cup of softened butter, 1/4 cup of brown sugar, and 1/2 cup of all-purpose flour with a pinch of salt. Crumble until it resembles coarse crumbs. Spread on a baking sheet and bake at 350°F (177°C) for about 15 minutes or until golden, stirring halfway through.

Once chilled, remove the cheesecake from the springform pan. Drizzle salted caramel sauce over the cheesecake. Spoon the cooled apple mixture on top, followed by the streusel topping. Serve with additional caramel drizzle and cream cheese frosting if desired.