Aethionema
We've grown a couple of these stonecresses, A. grandiflorum and A. pulchellum. They are part of the Brassicaceae family, so have 4-petalled flowers, pink or white, in rounded heads. Remarkably there are around 60 species, almost all from Turkey. They are good for drought-type garden, in full sun and normally grow on limestone rocks. They should be very suitable for a rock, or crevice garden and but are also happily growing in our scree garden.
A valuable source of nectar and pollen to butterflies in particular in drought-prone or rocky gardens. The leaves could also conceivably be eaten by caterpillars of green-veined white and other 'cabbage' whites that feed mostly on plants in the Brassicaceae family.