Preheat oven to 325°F (163°C). Mix graham cracker crumbs, sugar, and melted butter in a medium bowl. Stir until combined. Press firmly into the bottom of a 9-inch springform pan. Set aside.
In a small bowl, combine brown sugar and cinnamon. Stir in melted butter until crumbly. Set aside.
In a large bowl, beat softened cream cheese and sugar until smooth. Add vanilla extract and mix well. Add eggs one at a time, mixing thoroughly after each. Stir in sour cream and heavy cream until fully blended.
Pour half the cheesecake filling over the crust and spread evenly. Spoon half the cinnamon filling over it, then swirl gently with a knife. Repeat with remaining cheesecake filling and cinnamon mixture, swirling again on top.
Bake for 60–70 minutes until edges are set and center has a slight jiggle. Turn off oven, crack door, and let cheesecake cool inside for 1 hour. Then refrigerate for at least 4 hours or overnight.
Whisk powdered sugar, milk, and vanilla extract in a small bowl until smooth. Drizzle over the chilled cheesecake just before serving.