The Munich Compact Light Source (MuCLS)* is a compact synchrotron source based on inverse Compton X-ray scattering. This effect produces brilliant quasi-monochromatic hard X-ray radiation with rather low electron energy (tens of MeV) by colliding these electrons head-on with a laser beam. Such sources are sufficiently compact to fit into a laboratory or industrial environment enabling a more widespread use of synchrotron techniques**. Many of these techniques are affected detrimentally by a larger (projected) source size, e.g. X-ray phase contrast imaging. The more precisely the exact shape of the source is determined, the better can its effects be corrected for in the recorded data. We experimentally evaluate a novel approach to obtain an accurate 2D X-ray source profile***. A hole in a strongly absorbing structure is used to record the edge-spread function azimuthally resolved in a single shot. The 2D source spot is retrieved from this data by taking the derivative of the edge-spread function and applying the filtered-backprojection algorithm of computed tomography. We discuss results obtained for the source shape and relate them to general performance parameters of the MuCLS.