  We propose a novel means of directly measuring cosmological distances using
scintillated microlensing of fast radio bursts (FRBs). In standard strong
lensing measurements of cosmic expansion, the main source of systematic
uncertainty lies in modeling the mass profile of galactic halos. Using
extra-galactic stellar microlensing to measure the Hubble constant avoids this
systematic uncertainty as the lens potential of microlenses depends only on a
single parameter: the mass of the lens. FRBs, which may achieve nanosecond
precision on lensing time delays, are well-suited to precision measurements of
stellar microlensing, for which the time delays are on the order of
milliseconds. However, typical angular separations between the microlensed
images on the order of microarcseconds make the individual images impossible to
spatially resolve with ground-based telescopes. We propose leveraging
scintillation in the ISM to resolve the microlensed images, effectively turning
the ISM into an astrophysical-scale interferometer. Using this technique, we
estimate a 6\% uncertainty on $H_0$ from a single observed scintillated
microlensing event, with a sub-percent uncertainty on $H_0$ achievable with
only 30 such events. With an optical depth for stellar microlensing of
$10^{-3}$, this may be achievable in the near future with upcoming FRB
telescopes.
