In a large mixing bowl, use a fork to toss the graham cracker crumbs, sugar, and cinnamon together. Add the melted butter, mixing until all crumbs are moistened. Press mixture into the bottom and up the sides of a 9-inch springform pan. Refrigerate while you work on the batter.

Preheat the oven to 325ºF. In the bowl of a stand mixer fitted with the paddle attachment, beat cream cheese on high until creamy, about 2-3 minutes. Add both sugars and continue beating for another 2-3 minutes. Scrape down the sides of the bowl, add the cornstarch, vanilla, and salt, and beat until incorporated, 1-3 minutes. Beat in the eggs, two at a time, until combined. Try not to overmix. Set aside, while you make the filling.

In a medium bowl stir the butter, brown sugar, cinnamon, and flour together until smooth.

Pour a third of the batter into the crust, then spoon teaspoon-sized dollops of the filling evenly over the batter. You'll use about a third of the filling. Add another third of the batter on top, followed by another third of the filling. Repeat steps with the remaining batter and filling. Use a knife to slightly swirl the filling into the batter.

Wrap the springform pan in foil (make sure the foil goes all the way up the sides of the pan), and place it into roasting large pan. Fill the roasting pan with hot water until it reaches about halfway up the sides of the springform pan.

Bake cheesecake for 1 hour and 20 minutes, or until center appears nearly set when shaken. Turn off the oven, and leave the cheesecake in the oven for 30 minutes with the oven door slightly open.

Remove cheesecake from the oven and place on a wire rack. Allow to cool for at least 2 hours before removing aluminum foil, covering cheesecake and chilling in the refrigerator for at least 8 hours.

In a medium bowl, beat the butter until light and creamy. Beat in the powdered sugar, a 1/2 cup at a time, until smooth. Add the vanilla and heavy cream/milk, beating until whipped and combined.

Once cheesecake is properly chilled, run a knife around the sides of the cheesecake to loosen the pan. Unhinge the springform pan sides and place cheesecake onto a plate or pedestal. Pour icing on top of cooled cheesecake, and spread out evenly with an offset spatula or butter knife. Slice into pieces and serve, or refrigerate until ready to eat.