Bring cider to boil. Add sugar and stir until dissolved. Remove from heat. Stir in rum, brandy, apple brandy, orange liqueur, spices, and salt. Stir in orange juice concentrate. Heat over moderate heat, stirring, for 2 minutes. Pour into demitasse cups or wine glasses and top with a generous dollop of sweetened whipped cream. (The whipped cream makes a big difference in the finished taste of the drink – don’t omit it.) Garnish with fresh nutmeg if desired.