Line 9 x 13 pan with tin foil that hangs over edge for ease in removing bars and cutting. Spray with pam. In a small bowl, combine graham cracker crumbs and 1/3 cup sugar; stir in butter. Press into prepared pan. In a small bowl, beat cream cheese and 2/3 cup sugar until smooth. Beat in 2 eggs just until blended. Pour over crust. Bake at 350° for 20-25 minutes or until set. Cool on a wire rack.
Meanwhile, separate remaining eggs and set whites aside. In a large saucepan, combine the yolks, pumpkin, brown sugar, milk, salt and cinnamon. Cook and stir over low heat for 10-12 minutes or until mixture is thickened and reaches 160°. Remove from the heat.
In a small saucepan, sprinkle gelatin over cold water; let stand for 1 minute. Heat over low heat, stirring until gelatin is completely dissolved. Stir into pumpkin mixture; set aside. In a large heavy saucepan, combine reserved egg whites and remaining sugar. With a portable mixer, beat on low speed for 1 minute. Continue beating over low heat until mixture reaches 160°, about 12 minutes. Remove from the heat; beat until stiff glossy peaks form and sugar is dissolved. Fold into pumpkin mixture; spread evenly over cream cheese layer. Cover and refrigerate for 4 hours or until set. When ready to cut, remove by lifting out with tin foil. cut with sharp knife on cutting board. If served as a big dessert (4 x 4 inches), serve with whipped cream. But as a little bite, it was great without cream.
**This was a bit labor intensive, and I wasn’t sure it was worth it, but the finished product was so yummy! I might try to simplify the pumpkin layer.