  Protected by an approximate shift symmetry, axions are well motivated
candidates for driving cosmic inflation. Their generic coupling to the
Chern-Simons term of any gauge theory gives rise to a wide range of potentially
observable signatures, including equilateral non-Gaussianites in the CMB,
chiral gravitational waves in the range of direct gravitational wave detectors
and primordial black holes (PBHs). In this paper we revisit these predictions
for axion inflation models non-minimally coupled to gravity. Contrary to the
case of minimally coupled models which typically predict scale-invariant mass
distributions for the generated PBHs at small scales, we demonstrate how
broadly peaked PBH spectra naturally arises in this setup. For specific
parameter values, all of dark matter can be accounted for by PBHs.
