IC package assemblies including a molding compound in which an IC chip surface is recessed relative to the molding compound. Thickness of the IC chip may be reduced relative to its thickness during the molding process. Another IC chip, heat spreader, etc. may then occupy the resultant recess framed by the molding compound to achieve a fine stacking pitch. In some embodiments, a package-on-package (PoP) assembly includes a center-molded IC chip flip-chip-bonded to a first package substrate. A second substrate to which a second IC chip is flip-chip bonded is then electrically coupled to the first substrate by through-molding vias. Within the PoP assembly, the second IC chip may be disposed back-to-back with the center-molded IC chip so as to occupy the recess framed by the molding compound.