This is a brass cast and engraved platter (thali) from the Deccan region. In the centre is a pair of cows, and around them is a depiction of the Dashavatara of Vishnu and Ganesh. On the back of the platter, there is an engraving in Kannada saying 'Yajama', probably commissioned by the owner or the donor. This platter would have been used in puja or worship rituals.
The Dashavatara refers to the ten primary (i.e. full or complete) incarnations (avatars) of Vishnu, the Hindu God of preservation. The word Dashavatara is derived from 'dasa' meaning ten, and 'avatar', roughly translating to 'incarnation'.