  Twisted graphene based moir\'e heterostructures host a flat band at the magic
angles where the kinetic energy of the charge carriers is quenched and
interaction effects dominate. This results in emergent phases such as
superconductors and correlated insulators that are electrostatically tunable.
We investigate superconductivity in twisted trilayer graphene (TTG) by
integrating it as the weak link in a superconducting quantum interference
device (SQUID). The measured current phase relation (CPR) yields a large and
tunable kinetic inductance, up to 150 nH per square, of the electron and hole
type intrinsic superconductors. We further show that the specific kinetic
inductance and the critical current density are universally related via the
superconducting coherence length, and extract an upper bound of 200 nm for the
coherence length. Our work opens avenues for using graphene-based
superconductors as tunable elements in superconducting circuits.
