Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9-inch springform pan.

Combine graham cracker crumbs and 1/4 cup white sugar in a bowl; stir in butter. Press crust onto the bottom and 1 1/2-inches up the side of prepared springform pan.

Bake in preheated oven until set and lightly browned, 5 to 7 minutes. Cool for 10 minutes.

Meanwhile, beat cream cheese and brown sugar in a large bowl until smooth. Stir pumpkin, cornstarch, 1 1/4 teaspoons cinnamon, and nutmeg into cream cheese mixture. Gradually beat in evaporated milk and eggs until just blended; pour into crust. Place pan on a baking sheet.

Bake in preheated oven until center is almost set, 55 to 60 minutes.

Combine sour cream, 1/3 cup white sugar, and vanilla extract in a small bowl. Spread sour cream topping over cheesecake and bake 5 minutes longer. Cool on wire rack for 10 minutes, then carefully run a knife around edge of pan to loosen; cool 1 hour then refrigerate overnight.

Remove sides of pan; let stand at room temperature 30 minutes before slicing. Sprinkle with cinnamon.