Oyster sauce is a dark brown sauce made by cooking oysters with soy sauce and brine until the mixture is thick and concentrated. The rich flavor of oyster sauce is popular in Asian stir-fries and as a condiment to Asian foods.
Garnish the ribs with green onion brushes. To make brushes, trim the onions to 3-inch lengths and make several length-wise cuts through each onion, leaving about 1 inch of white onion intact. Place in ice water until cut onion curls back.