1. first take a large bowl fill it half way with ice and set aside.
2.Whisk the yolks, 3/4 cup plus 2 tablespoons sugar, and 3/4 cup cream together in a medium saucepan. Heat while stirring continuously with a rubber spatula or wooden spoon over medium-low heat, until thickened and the mixture coats the spatula -- about 10 minutes. Transfer to a medium bowl and set over the ice bath . Stir to cool.
3. Add pumpkin, vanilla, spices , and salt to the egg mixture. Stir 1 tablespoon rum and 1 teaspoon gelatin together in a small bowl. Heat the remaining tablespoon rum, and stir in to the gelatin mixture until dissolved. Gently whisk into the pumpkin mixture. Beat 1/2 cup cream to stiff peaks, and fold into pumpkin mixture. Pour into a shallow dish, cover and chill until cold and thick enough to fall from a spoon in heavy dollops -- about 8 hours or up to overnight.
4. Beat the remaining cream and sugar to stiff peaks. Alternately layer the pumpkin mousse and whipped cream in a glass serving dish. Sprinkle the chocolate shavings between top two layers. Serve chilled.