In small bowl mix crushed pretzels, sugar, and melted butter. Press into a greased 13x9 baking dish
In small bowl mix cream cheese and 2/3 cup sugar beat until smooth. Beat in 2 eggs until just blended pour over pretzel crust and bake at 350 for 20-25 min or until set Cool on wire rack.
Meanwhile separate remaining eggs and set egg whites to the side. In a large saucepan combine yolk, pumpkin, brown sugar, milk, and salt and cinnamon. Cook and stir over low heat for 10=12 min or until mixture is thickened and reaches 160 Remove from heat.
In small saucepan sprinkle gelatin over cold water let it stand for 1 min Heat over low heat stirring until gelatin is compeletely dissolved, stir into pumpkin mixture sit aside
In large heavy saucepan combine reserved egg whites and remaining sugar. With a portable mixer beat on low for 1 min Continue beating over low heat until temp reaches 160 about 12 min Remove from heat and beat until stiff glossy peaks and sugar is dissolved
Fold into pumpkin mixture spread evenly over cream cheese layer. Cover and refrig for 4 hours. Serve with whipped topping.