The liquid phase separation behaviour of metastable monotectic Co-Cu alloys was investigated as a function of cooling rate using a 6.5 m drop-tube facility. A range of liquid phase separated morphologies were observed including stable two-layer core-shell, evolving core-shell and dendritic structures. It was found that in the core-shell structures the core was always in the higher melting point (Co-rich) phase, irrespective of the core and shell volume fraction. In Cu-50 at% Co alloy, high cooling rates were observed to yield two episodes of liquid phase separation, corresponding to binodal, followed by spinodal decomposition. The resulting structure comprised a core-shell structure in which the Co-rich core contained a very fine dispersion of Cu-rich particles with a Cu-rich shell which may, or may not, contain a similar dispersion of Co-rich particles.