  The ability to measure detailed aspects of the substructure of high-energy
jets traversing the quark-gluon plasma (QGP) has provided a new window into its
internal dynamics. However, drawing robust conclusions from traditional jet
substructure observables has been difficult. In this manuscript we expand on a
new approach to jet substructure in heavy-ion collisions based on the study of
correlation functions of energy flow operators (energy correlators). We compute
the two-point energy correlator of an in-medium massless quark jet and perform
a detailed numerical analysis of the produced spectra. Our calculation
incorporates vacuum radiation resummed at next-to-leading log accuracy together
with the leading order contribution in medium-induced splittings evaluated
through the BDMPS-Z multiple scattering and GLV single scattering formalisms
for a static brick of QGP. Our analysis demonstrates how particular features of
the modifications of in-medium splittings are imprinted in the correlator
spectra, particularly showing how energy correlators may be used to extract the
onset of colour coherence. We further present a comprehensive discussion on the
accuracy and limitations of our study emphasizing how it can be systematically
improved. This work sets the foundations for a rich program studying energy
correlators in heavy-ion collisions.
