Pour the sugar into an even layer in a large saucepan and heat on medium-high, whisking until melted.

Once the sugar has melted, stop whisking and cook until it turns a darker amber color, then remove from heat.

Whisk in the butter until combined, then slowly pour in the heavy cream, whisking until smooth.

Set about 1 cup of caramel aside for topping, then add flour and pecan chips to the remaining caramel and set aside.

Preheat oven to 325°F (163°C).

Line a 9-inch (23cm) springform pan with parchment paper and grease the sides.

Combine graham cracker crumbs, melted butter, and brown sugar in a bowl and press mixture into the pan.

Bake the crust for 10 minutes, then set aside to cool.

Reduce oven temperature to 300°F (148°C).

Pour the caramel with pecans and flour into the crust and spread into an even layer.

Prepare the chocolate ganache by heating heavy cream to boiling, then pouring it over chocolate chips, letting sit, and whisking until smooth.

Pour the ganache over the caramel sauce and spread evenly.

Beat cream cheese, brown sugar, and flour on low speed until smooth, scraping sides as needed.

Mix in sour cream and vanilla extract.

Add eggs one at a time, mixing slowly after each addition.

Pour cheesecake batter into the crust over the chocolate layer.

Place the springform pan inside a larger pan and fill the outer pan with warm water halfway up the sides.

Bake for 1 hour and 35 minutes. The center should jiggle slightly.

Turn off the oven and let the cheesecake cool in the oven with the door closed for 30 minutes.

Crack the door open for another 30 minutes before removing.

Pour the reserved caramel sauce over the cooled cheesecake and spread evenly.

Refrigerate cheesecake until completely cool and firm, about 5-6 hours.

For the drizzle, prepare remaining chocolate ganache in the same way as before and drizzle over the cheesecake.

Slice and serve with extra pecan chips and optional whipped cream.