Preheat oven to 350 degrees.
For the first layer, mix together the graham cracker crumbs, melted butter and 1/4 cup sugar.
Press into the bottom of a 9 x 13 pan.
For the second layer, beat together the softened cream cheese, 2 eggs and 1/2 cup of sugar.
Pour over the graham cracker crust.
Bake for 20 minutes.
Allow to cool.
For the top layer, combine the pumpkin, 3 egg yolks, 1/4 cup sugar, milk, salt and cinnamon in a sauce pan. Cook over medium high heat until the mixture bubbles. Allow to cook for 5 minutes, while stirring continually.
Dissolve 1 envelope of gelatin in 1/4 cup of cold water.
Stir into the pumpkin mixture and then allow everything to cool.
Pour over the cooled cream cheese layer.
Refrigerate for a few hours before serving.
Serve with whipped cream.
