Final answer:
The masonry technique used in Zoser's mortuary complex was stacking stone mastabas to form a step pyramid, a method innovated by architect Imhotep.
Step-by-step explanation:
The masonry technique used in Egyptian buildings such as Zoser's mortuary complex is known for its revolutionary construction method involving stacking stone mastabas. Imhotep, the architect of Pharaoh Djoser, is credited with the innovation of building the earliest large stone structure a step pyramid which was a series of stacked mastabas that formed a towering stone pyramid with a complex of temples and burial chambers beneath it.
This method set a standard for future Egyptian masonry practices and became a hallmark of their architectural expertise.