We present the development of a continuous-wave method of quantifying the optical properties of a two-layered model of the human head using a broadband spectral approach. Absolute absorption and scattering properties of the upper and lower layers of phantoms with known optical properties were reconstructed from steady-state multi-distance measurements by performing differential fit analysis of the near-infrared reflectance spectrum between 700 and $1000\mathrm{nm}$ . From spectra acquired at 10, 20, and $30\mathrm{mm}$ , the concentration of a chromophore in the bottom layer was determined within an error of 10% in the presence of a $15\mathrm{mm}$ thick top layer. These results demonstrate that our method was able to determine the optical properties of the lower layer, which represents brain, with acceptable error at specific source–detector distances.