Preheat your oven to 350°F (175°C). In a medium mixing bowl, combine crushed graham crackers with melted butter and sugar until well mixed. Press into the bottom of a 9-inch springform pan. Bake for 8 minutes until lightly golden, then allow to cool.

In a small bowl, mix together the cinnamon and sugar for the swirl and set it aside. For the streusel topping, combine flour, brown sugar, and cold butter in a separate bowl. Use your fingers or a pastry cutter to mix until the mixture resembles coarse crumbs.

In a large mixing bowl, beat the room-temperature cream cheese and sugar using a hand mixer until smooth and creamy, about 2 minutes. Gradually add in sour cream, flour, salt, and vanilla extract, mixing just until combined. Carefully beat in the eggs, one at a time.

Pour half of the cheesecake filling into the cooled crust. Sprinkle the prepared cinnamon sugar mixture evenly over the filling. Dollop the remaining filling over the cinnamon layer, then use a knife to lightly swirl it together.

Place the springform pan in a larger baking dish and add hot water to create a water bath. Bake for about 1 hour and 40 minutes, until the edges are set but the center is still slightly jiggly.

Once baked, turn off the oven, crack the door open, and let the cheesecake cool inside for 30 minutes. Run a knife around the edges and cool completely at room temperature before refrigerating for at least 4 hours.

If desired, whisk together powdered sugar and milk for icing. Drizzle over the cooled Coffee Cake Cheesecake just before serving.