Steak -, dish of raw mince, raw egg and onion (7)
I believe the answer is:
tartare
(Other definitions for tartare that I've seen before include "(Of fish or beef) served chopped and raw in small cakes" , "Mayonnaise-based sauce with capers, eaten with fish" , "(Mayonnaise) sauce; raw (steak)" , "Type of mayonnaise sauce" , "9, 7" .)