Using ethylene glycol dimethacrylate (EGDMA) as a cross-linker Gibbsite platelets were successfully encapsulated fully using an ATRP-mediated emulsion polymerisation technique. Previously we reported a “muffin-like” morphology, which was obtained using the same approach without a cross-linker. This morphology was attributed to the mobility of the growing polymeric chains, allowing them to move one side of the platelet during the reaction. The addition of EGDMA reduces this mobility and it is shown that this approach indeed leads to encapsulated Gibbsite. A comprehensive study of the reaction conditions, in particular the cross-linker addition profile and concentration, was carried out in combination with cryo-TEM characterization of the final particle morphology.