Fruitcake Trifle

Directions

1. 1
   In a bowl whisk together the yolks and the sugar and add the milk, scalded with the zest, in a slow stream, whisking.
2. 2
   In a heavy saucepan combine the yolk mixture and the heavy cream and cook the custard over moderately low heat, stirring constantly with a wooden spoon, until it registers 175F.
3. 3
   on a candy thermometer.
4. 4
   Pour the custard into a metal bowl and whisk in the vanilla and the sour cream.
5. 5
   In a small saucepan sprinkle the gelatin over 1/4 cup cold water, let it soften for 1 minute, and heat the mixture over moderate heat, stirring, until the gelatin is dissolved.
6. 6
   Stir the gelatin mixture into the custard, set the bowl in a larger bowl of ice and cold water, and chill the custard, stirring occasionally, until it is the consistency of raw egg white.
7. 7
   Line the bottom of a 1 1/2-quart glass bowl with some of the fruitcake slices, pour in the custard, and push the remaining fruitcake slices into the custard in decorative patterns.
8. 8
   Chill the trifle, covered, for at least 2 hours or overnight.