pepper steak vs peppered steak

pepper steak and peppered steak both are nouns.

Word	Noun	Adjective	Verb	Adverb
pepper steak	Yes	No	No	No
peppered steak	Yes	No	No	No

As nouns, pepper steak and peppered steak are synonyms defined as:

pepper steak and peppered steak: steak covered with crushed peppercorns pan-broiled and served with brandy-and-butter sauce

Other synonyms of pepper steak include steak au poivre.

pepper steak (noun)	peppered steak (noun)
strips of steak sauteed with green peppers and onions	steak covered with crushed peppercorns pan-broiled and served with brandy-and-butter sauce
steak covered with crushed peppercorns pan-broiled and served with brandy-and-butter sauce