In a large saucepan, melt chocolate chips over low heat; stir until smooth. In a small bowl, combine the milk, egg yolks and sugar; gradually add to chocolate, stirring constantly. Cook and stir for 2-3 minutes. Remove from the heat; cool to room temperature. Fold in cream.
Tear cake into bite-size pieces; place half in a greased 13-in. x 9-in. dish. Top with half of the chocolate mixture. Repeat layers. Cover and refrigerate overnight. Serve chilled.