  Quantum Hall (QH) interferometry provides an archetypal platform for the
experimental realization of braiding statistics of fractional QH states.
However, the complexity of observing fractional statistics requires phase
coherence over the length of the interferometer, as well as suppression of
Coulomb charging energy. Here, we demonstrate a new type of QH interferometer
based on marginally twisted bilayer graphene (mtBLG), with a twist angle
$\theta$ $\approx$ $0.16$ $^{\circ}$. With the device operating in the QH
regime, we observe distinct signatures of electronic Fabry-P\'{e}rot (FP) and
Aharonov-Bohm (AhB)-oscillations of the magneto-thermopower in the
density-magnetic field phase-space, at Landau level filling factors
$\nu=4$,$8$. We find that QH interference effects are intrinsic to the
triangular AB/BA domains in mtBLG that show diminished Coulomb charging
effects. Our results demonstrate phase-coherent interference of QH edge modes
without any additional gate-defined complex architecture, which may be
beneficial in experimental realizations of non-Abelian braiding statistics.
