Roast the Pumpkin (21 ounce).
Scoop and measure pumpkin flesh. Puree pumpkin in a food processor, or in a large bowl with an immersion blender and blend until smooth.
In a large bowl, combine the pumpkin with Ground Cinnamon (1 1/2 teaspoon), Ground Ginger (3/4 teaspoon), Ground Nutmeg (1/3 teaspoon), Salt (1/3 teaspoon), Vanilla Extract (3 teaspoon) and Spiced Rum (3 tablespoon). Mix well.
Prepare an ice bath in a large bowl filled halfway with ice water.
Separate the yolks of 7 Egg (7). Save the whites for another purpose.
Combine egg yolks in a small sauce pan with the Granulated Sugar (3/4 cup) and Heavy Cream (1 cup). Cook slowly over low heat while constantly stirring until thick enough to coat the back of the spoon, about 10 to 15 minutes.
Transfer the custard to a heatproof bowl, set it in an ice-bath and stir until it is cool.
Stir the custard into the pumpkin mixture until well combined.
In a separate bowl, beat Heavy Cream (3/4 cup) until it roughly doubles in volume and stiff peaks are formed.
Fold half of the whipped cream into the pumpkin to lighten the mixture. Then add remaining whipped cream and gently fold until completely incorporated.
Spoon mousse into cups for individual servings, or into a serving bowl or terrine. Chill until set – several hours or overnight.
Before serving, whip Heavy Cream (1 cup) with Powdered Confectioners Sugar (1 tablespoon) and 3 tablespoon vanilla-infused rum until soft peaks form. Top mousse with whipped cream and garnish with Dark Chocolate (to taste).