  Using van der Waals tunnel junctions, we perform spectroscopy of
superconducting $\mathrm{NbSe_2}$ flakes, of thicknesses ranging from 2--25
monolayers, measuring the quasiparticle density of states as a function of
applied in-plane magnetic field up to 33T. In flakes up to $\approx$ 15
monolayers thick, we find that the density of states is well-described by a
single band superconductor. In these thin samples, the magnetic field acts
primarily on the spin (vs orbital) degree of freedom of the electrons, and
superconductivity is further protected by Ising spin-orbit coupling (ISOC),
which pins Cooper pair spins out-of-plane. The superconducting energy gap,
extracted from our tunnelling spectra, decreases as a function of the applied
magnetic field. However, in bilayer $\mathrm{NbSe_2}$, close to the critical
field (up to 30T, much larger than the Pauli limit), superconductivity appears
to be even more robust than expected if only ISOC is considered. This can be
explained by a predicted subdominant triplet component of the order parameter,
coupled to the dominant singlet component at finite field. This equal-spin,
odd-parity triplet state arises from the non-colinearity between the applied
magnetic field and the Ising field.
