Preheat your oven to 325°F (160°C). In a medium bowl, mix the graham cracker crumbs, melted butter, and sugar until combined. Press this mixture firmly into the bottom of a 9-inch springform pan, forming an even layer. Bake for about 10 minutes and allow to cool while preparing the filling.

In a large mixing bowl, beat the softened cream cheese and granulated sugar together until smooth and fluffy. Add the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract, sour cream, cornstarch, and butterscotch sauce until fully combined.

Pour the cheesecake filling over the cooled crust, smoothing the top with a spatula. Bake in the preheated oven for 50-60 minutes. The cheesecake should be set around the edges but still slightly jiggly in the center.

Once baked, turn off the oven and crack the door open slightly. Allow the cheesecake to cool in the oven for about 1 hour to help prevent cracking.

After the cheesecake has cooled, refrigerate it for at least 4 hours, ideally overnight. Before serving, drizzle additional butterscotch sauce on top and garnish with whipped cream and optional toppings like chopped nuts or toffee bits.