Investment casting cores and methods

An investment casting pattern is formed by forming a metallic first core element (50) including at least one recess (34). The first core element (50) is engaged to at least a mating one of an element (60) of a die and a second core element. The recess (34) serves to retain the first core element (50) relative to the mating one. The die is assembled and a sacrificial material is introduced to the die to at least partially embed the first core element. The recess (34) may be pre-formed prior to cutting the first core element (50) from a larger sheet of material.