The synthesis of patchy colloidal spheres with well-controlled number of patches at their surface leads to interesting gold nanostructures. They allow to design and synthesis hollow nanoscale structure with a control porosity and composition as well as nanorattle-like nanostructures through filling of the nanocages with a guest nano-object. They also offer the possibility to make highly symmetric plasmonic clusters of subwavelength-scale, in which the metal surfaces are separated by nanoscale gaps. These latter leads to interesting physics. They have remarkable optical properties that can result in the generation of optical magnetism. This amazing effect is of interest for the development of applications in a range of exciting new research fields : cloaking, imaging, and optical communications. For such applications, the morphology must be precisely controlled : a modification of the number of plasmonic nanoparticles or a variation of just a few nanometers in the gap distances between different nanoparticles within the clusters can affect the collective modes and resonances and would broaden or weaken the bulk optical response. In this talk, I will show how to produce these plasmonic nanostructures with exotic properties by combining multiple synthesis steps involving inorganic growth, polymerization, and metal deposition. This multi-step colloidal synthesis approach allows a high degree of control over morphology, high precision, and the ability to scale up the fabrication to bulk quantities.