Preheat your oven to 325°F (160°C). Grease the bottom and sides of a 9-inch springform pan with butter or cooking spray.

In a mixing bowl, combine the graham cracker crumbs, melted butter, granulated sugar, and ground cinnamon until well mixed. Press this mixture firmly into the bottom of the springform pan to form the crust.

In another large mixing bowl, beat the softened cream cheese with an electric mixer on medium speed until smooth and creamy. Gradually add the granulated sugar and continue to mix until combined.

Add the eggs one at a time, mixing well after each addition. Then add the vanilla extract, ground cinnamon, and sour cream. Mix until smooth and well combined.

Pour the cheesecake filling over the prepared crust in the springform pan. Smooth the top with a rubber spatula.

Bake in the preheated oven for about 60 minutes, or until the center is set and only slightly jiggles when gently shaken.

Turn off the oven and crack the door open, allowing the cheesecake to cool in the oven for 30 minutes to prevent cracking.

Remove the cheesecake from the oven and let it cool to room temperature, then refrigerate for at least 4 hours or overnight.

To make the topping, whisk together the softened cream cheese, powdered sugar, milk, and vanilla extract in a mixing bowl until smooth.

Once the cheesecake has chilled, remove it from the springform pan and drizzle the cream cheese topping over the cheesecake before serving.