An apparatus and method are described for stacking a plurality of cores. For example, one embodiment of an apparatus comprises: a package; an uncore die mounted on the package, the uncore die comprising a plurality of exposed landing slots, each landing slot including an inter-die interface usable to connect vertically to a cores die, the uncore die including a plurality of uncore components usable by cores within the cores die including a memory controller component, a level 3 (L3) cache, a system memory or system memory interface, and a core interconnect fabric or bus; and a first cores die comprising a first plurality of cores, the cores spaced on the first cores die to correspond to all or a first subset of the landing slots on the uncore die, each of the cores having an inter-die interface positioned to be communicatively coupled to a corresponding inter-die interface within a landing slot on the uncore die when the first cores die is vertically coupled on top of the uncore die, wherein the communicative coupling between the inter-die interface of a core and the inter-die interface of its corresponding landing slot communicatively couples the core to the uncore components of the uncore die.