Full Idea
The route into essentialism is, first, a recognition that the essence of a thing is "what it is to be" that (kind of) thing; the essence of a thing is just its identity.
Gist of Idea
Essences are what it is to be that (kind of) thing - in fact, they are the thing's identity
Source
Scott Shalkowski (Essence and Being [2008], 'Essent')
Book Reference
'Being: Developments in Contemporary Metaphysics', ed/tr. Le Poidevin,R [CUP 2008], p.49
A Reaction
The first half sounds right, and very Aristotelian. The second half is dramatically different, controversial, and far less plausible. Slipping in 'kind of' is also highly dubious. This remark shows, I think, some confusion about essences.