They make small hamburgers that seem to be steamed cooked with onions.
Their frozen patties have holes in them which disappear after cooking, must save them meat and money.
In the southeastern states, there is a chain called Krystal that sells similar burgers but I think they have mustard on them. That chain has been in financial difficulty over some of the past, with various owners over time, if I remember right. It started in Tennessee I believe.