  Hawking evaporation of primordial black holes (PBHs) can facilitate the
generation of matter-antimatter asymmetry. We focus on ultra-low mass PBHs that
briefly dominate the universe and evaporate before the big bang
nucleosynthesis. We propose a novel test of this scenario by detecting its
characteristic doubly peaked gravitational wave (GW) spectrum in future GW
observatories. Here the first order adiabatic perturbation from inflation and
from the isocurvature perturbations due to PBH distribution, source tensor
perturbations in second-order and lead to two peaks in the induced GW
background. These resonant peaks are generated at the beginning of standard
radiation domination in the presence of a prior PBH-dominated era. This unique
GW spectral shape would provide a smoking gun signal of non-thermal
baryogenesis from evaporating PBHs, which is otherwise impossible to test in
laboratory experiments due to the very high energy scales involved or the
feeble interaction of the dark sector with the visible sector.
