Preheat oven to 350 degrees. Grease a 9 inch springform pan. In medium bowl, combine graham cracker crumbs, sugar, and cinnamon, and then stir in melted butter. Press into bottom and sides of springform pan. Set aside.

In a large bowl, mix cream cheese with sugar until smooth. Blend in milk, and then mix in the eggs one at a time, mixing just enough to incorporate. Mix in sour cream, vanilla, and flour until smooth. Pour filling into prepared crust.

Bake in preheated oven for 1 hour. Turn the oven off, and let cake cool in oven with the door closed for 5 to 6 hours; this prevents cracking. Chill in refrigerator until serving. Better if served the day after baking.