We propose a compact setup for wavefront manipulation in spectral domain optical coherence tomography (OCT). The system can easily be implemented into existing free-space OCT setups through modification of the source path only. We demonstrate complex-valued OCT signal acquisition based on phase shifting combined with iterative optical wavefront shaping, which locally enhances the OCT signal acquired from within a scattering sample. The system lends itself to future imaging studies in strongly scattering media such as biological tissue.