Zinc oxide (ZnO) is non-toxic and chemically and mechanically stable. Additionally, ZnO displays NLO properties that can be modulated by chemical doping. In particular, aluminum doped zinc oxide (AZO) exhibits a vanishing real part of the permittivity in the near-infrared (near-IR) range, classifying it as an epsilon-near-zero (ENZ) material. The level of aluminum doping controls the wavelength at which the permittivity crosses zero, providing an additional dimension of tunability. ENZ materials have been recently suggested as promising materials for NLO, thanks to their sizeable nonlinear susceptibility that combines with the strong field enhancements at specific wavelength, typically set in the NIR region of the spectrum. This phenomenon, known as ENZ condition, occurs in transparent conducting oxides when the real part of the electric permittivity approaches zero yielding a metal-like behavior. An ideal system to combine plasmonic near-field enhancement with ENZ materials could therefore be composed of a gold core coated with an aluminum-doped ZnO shell, in which the size and shape of the core, and the thickness and dopant level of the shell are tunable at will. While it is possible to synthesize Au@ZnO core@shell nanoparticles by combining the colloidal synthesis of the metallic cores to a sol-gel step for the formation of an oxide shell, previous studies did not focus on tailoring the structural parameters of the nanoparticles or led to the formation of a hydrated zinc hydroxide (Zn(OH)2) shell in the absence of an annealing final step. Additionally, no colloidal synthesis of Au@AZO core@shell nanoparticles has been reported, likely due to the high sensitivity of the sol-gel syntheses of AZO to the reactant concentrations, the pH level of the solution, the ratio of surfactant to ascorbic acid, and the temperature of the reaction. In this work, we demonstrate the colloidal synthesis of Au@ZnO and Au@AZO core@shell nanoparticles with controlled shell thickness, core size and shape, and aluminum dopant concentration. As a first step to demonstrate tunability of the synthetic process, we establish a procedure to vary the shell thickness of Au@ZnO NPs by varying the initial concentration of Au cores while keeping the concentration of the other the reactants constant. We then demonstrate that ZnO shells can easily be grown on spherical Au cores of different diameters as well as on gold nanorods. Finally, we develop a novel procedure to obtain Au@AZO nanoparticles by adding an aluminum doping step before calcination. We corroborate the synthetic results with UV-Vis spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), inductively coupled plasma mass spectrometry (ICP-MS), and numerical calculations of the extinction cross-section spectra of the core@shell nanoparticles.