  $R+R^2$ Supergravity is known to be equivalent to standard Supergravity
coupled to two chiral supermultiples with a no-scale K\"ahler potential. Within
this framework, that can accomodate vanishing vacuum energy and spontaneous
supersymmetry breaking, we consider modifications of the associated
superpotential and study the resulting models, which, viewed as generalizations
of the Starobinsky model, for a range of the superpotential parameters,
describe viable single-field slow-roll inflation. In all models studied in this
work the tensor to scalar ratio is found to be small, well below the upper
bound established by the very recent PLANCK and BICEP2 data.
