Frozen Chocolate Bourbon Parfaits

In a double boiler or a metal bowl set over a saucepan of barely simmering water melt chocolate in 1/2 cup water, stirring until smooth, and stir in bourbon until combined well. Remove top of double boiler or bowl from heat. In a large metal bowl with a hand held electric mixer beat eggs and granulated sugar until combined. Set bowl over a large saucepan of simmering water and beat mixture until light and thickened, about 6 minutes. In a very small saucepan sprinkle gelatin over remaining 2 tablespoons water and let stand 1 minute to soften. Heat gelatin mixture over moderate heat, stirring, until gelatin is dissolved. Beat chocolate and gelatin mixtures into egg mixture and cool to room temperature. In a bowl beat 1 1/2 cups cream until it just holds stiff peaks. Fold cream into chocolate mixture thoroughly and divide among eight 1 1/2-to 2-cup stemmed glasses. Freeze parfaits, covered with plastic wrap, until set, about 1 hour. In a bowl beat remaining 2 cups cream until it holds soft peaks. Sift confectioners' sugar over cream and beat until cream just holds stiff peaks. Transfer whipped cream to a pastry bag fitted with a decorative tip and pipe onto parfaits. Garnish with praline pieces. Freeze parfaits until solid, about 4 hours. Parfaits may be made 2 days ahead and frozen, covered. Let parfaits stand at room temperature 15 minutes before serving.