A method of fabricating microelectronic dice by providing or forming a first encapsulated die assembly and a second encapsulated die assembly. Each of the encapsulated die assemblies includes at least one microelectronic die disposed in a packaging material. Each of the encapsulated die assemblies has an active surface and a back surface. The encapsulated die assemblies are attached together in a back surface-to-back surface arrangement. Build-up layers are then formed on the active surfaces of the first and second encapsulated assemblies, preferably, simultaneously. Thereafter, the microelectronic dice are singulated, if required, and the microelectronic dice of the first encapsulated die assembly are separated from the microelectronic dice of the second encapsulated die assembly.