Frozen Chocolate Caramel Parfaits

From Gourmet Magazine February 2004

1/2 C whole milk
1 1/2 C chilled heavy cream
3 Tbsp water
3/4 C sugar
8 large egg yolks
7oz bittersweet chocolate, melted and cooled
1/2 tsp vanilla

Bring milk and 1/2 C cream just to a boil in a small heavy saucepan, then remove from heat and keep warm, covered. Bring water and 1/2 C sugar to a boil in another heavy saucepan, stirring until sugar is dissolved and washing down any sugar crystals on side of pan with a pastry brush dipped in cold water. Boil syrup, without stirring, gently swirling pan, until mixture is a deep golden caramel. Remove from heat and carefully add warm cream mixture (mixture will steam and caramel will harden). Cook over low heat, whisking, until caramel is dissolved. Whisk together yolks, remaining 1/4 C sugar, and a pinch of salt in a metal bowl, then add hot caramel mixture in a slow stream, whisking. Transfer custard to saucepan. Cook custard over moderately low heat, stirring, until thickened and registers 170 on thermometer. (do not let boil). Pour custard through a fine-mesh sieve into bowl of standing mixer, then beat at high speed 10 minutes (mixture will be completely cook, thick and pale). Beat in melted chocolate and vanilla. Whisk remaining cup cream in another bowl until it just holds stiff peaks, then whisk about one fourth of cream into chocolate mixture to lighten. Fold in remaining cream gently but thoroughly and divide mixture among paper cups, smoothing tops. Cover each cup with foil and freeze parfaits at least 12 hours. To serve, carefully tear off each paper cup and invert parfaits onto plates.

Serve with hot fudge sauce