Chocolate & Pistachio Parfait

1/2 cup shelled pistachios
6 egg yolks
1 cups sugar
6 tablespoons water
3 ounces semisweet chocolate
2 tablespoons orange liqueur or rum
3/4 teaspoon almond extract
2 drops green food coloring
2 cups heavy cream

If pistachios are salted, soak them in several changes of water and drain on paper towels.  Coarsely chop 1/3 cup of the nuts.  Beat egg yolks until smooth.  Combine 3.4 cup sugar and the water in a saucepan over medium heat and stir until sugar dissolves.  Bring to a boil and continue boiling 1 minutes  (to 220ºF on a candy thermometer).  Slowly drizzle this hot sugar syrup into yolks in a fine stream, beating on high speed until mixture is fluffy and falls in a thick ribbon from the beater,  10 to 15 minutes.  Put half this mixture into another large bowl.  Melt chocolate, stirring in a heat-proof bowl set over a pan of steaming hot water.  Beat the chocolate and liqueur into half the yolk mixture.  Stir almond extract, chopped nuts and the food coloring into remaining yolk mixture.  Beat cream and remaining 1.4 cup sugar until it hold soft peaks.  Fold half of the whip cream into each yolk mixture.  Alternate layers of pistachio and chocolate in small parfait glass or champagne flutes.  Cover and freeze until firm, 3 to 4 hours.  Garnish with the remaining pistachios.