In-N-Out’s Animal Style burger adds grilled onions, extra spread, and mustard-cooked beef.
Animal Style is part of the chain’s unofficial and semi-secret ordering tradition. The beef patty is cooked with mustard, then served with additional spread and grilled onions. The style can be requested on several burger configurations.
The phrase became widely known through word of mouth and fan culture rather than through a standard standalone menu heading. In-N-Out also uses other ordering terms, including Protein Style, which replaces the bun with lettuce.
Animal Style is sometimes mistaken for a separate burger name. It is better understood as a preparation style that modifies an order.