Lightly grease 8x4" loaf pan; line bottom and sides with waxed paper. Melt Beat in vanilla and chocolate mixture. Fold in 3 C of the La Creme. Stir in milk. Spread into lined pan. Chill until firm, about 4 hours. Unmold and remove waxed paper. Add liqueur to remaining La Creme. Cut terrine into slices and serve with topping mixture.