1. Steak-like. In reference to Steak.
2. Generally a positive comment of approval or recognition.
Steaky is derived from the word steak. Steak being a tasty peice of meat of high quality. Things that are steaky thus possess steak-like qualities without actually having any implied reference to the meat.
A: A love this band, their music is so steaky.
B: Their steakiness is unmatched.