Mix the eggs, sugar and salt in a heavy 2 quart saucepan. Gradually stir in the milk. Cook over medium heat for 10-15 minutes, stirring constantly, until the mixture just coats a metal spoon. Remove from the heat. Stir in 1 teaspoon vanilla.
Place the saucepan in cold water until the custard is cool. If the custard curdles, beat vigorously with a hand beater until smooth. Cover and refrigerate at least 2 hours but no longer than 24.
Just before serving, beat the whipping cream, powdered sugar and remaining vanilla in a chilled medium bowl with an electric mixer on high speed until stiff. Gently stir in 1 cup of the whipped cream, the rum and food colouring into the custard. Pour the custard mixture into a small punchbowl.
Drop the remaining whipped cream in mounds onto the custard mixture. Sprinkle with nutmeg. Serve immediately and refrigerate any leftovers.