A few weeks back I tried making my own White Castle sliders.
I nailed it.
I only did a batch of 12, but I have 60 going on the griddle tomorrow for some friends.
First, I rolled out the ground beef about 1/4 of an inch thick, and used a pizza cutter to cut the individual burgers.
Next I used a straw to punch out the 5 holes in the meat patty's.
Next, spread out the onions so the patty's have a bed to cook on
Put the burgers on top of the onions
And then put the buns on top of the meat.
Let them simmer about 7 min.
Then without flipping them, take them off the griddle and assemble the burgers.