White Castle has its own take on fast food hamburgers. For starters, the patties are square, with five holes in each patty. And they’re small, too –- two-and-a-half inch sliders. Just big enough to fit into the palm of your hand. And since they’re steamed on a bed of onions, everything is infused with this
Excellent listen throughout, but you can skip to 17:30 for competition with McDonalds.
That was White Castle that innovated that, see podcast.