Preheat oven to 350°F. Combine graham cracker crumbs, sugar, and cinnamon. Stir in melted butter. Press into a 13×9-inch baking dish.
Beat cream cheese until smooth. Add sugar and eggs, beating until fluffy. Pour over crust and bake for 15-20 minutes, or until set. Let cool.
In a double boiler, combine pumpkin, egg yolks, 1/2 cup sugar, milk, cinnamon, and salt. Cook until the mixture reaches 160°F. Stir in gelatin dissolved in cold water. Let cool.
Whisk egg whites with remaining sugar over low heat until they reach 160°F. Beat until stiff peaks form and fold into the pumpkin mixture. Pour over the cream cheese layer. Chill for 4 hours.
Beat heavy cream with sugar and vanilla until stiff peaks form. Spread over the pumpkin layer before serving.