Preheat oven to 350°.
For crust, drop graham crackers into plastic bag and crush with rolling pin or soda bottle. Mix crumbs, butter and sugar together and press into 9x13 baking pan.
For cream cheese layer, in a separate bowl, mix eggs, sugar and cream cheese. Pour over crust and bake 20 minutes.
For pumpkin layer, in a saucepan, heat pumpkin, egg yolks, 1/2 cup sugar, milk, salt and cinnamon until mixture thickens. Remove from heat and add gelatin that has been dissolved in cold water. Cool mixture.
For topping, beat egg whites, remaining sugar. Fold into pumpkin mixture. Pour over cooled cream cheese layer. Chill until ready to serve.
Top with whipped cream.