Onion smash-burger fatty melt

Slice shokupan to about half the thickness of a normal slice.

On a low griddle toast four slices of bread evenly on one side under press weights; this side becomes the inside of the grilled cheeses.

Season two 2-ounce balls of 80-20 ground beef with salt and pepper.

Melt a little butter on the griddle and toast the other sides; build two very thin grilled cheese sandwiches with American cheese, weighted, toasting both sides.

Slice the onion extremely thin on a mandolin across the grain, as for onion rings, to rupture more cells and get a more pungent onion.

Raise the griddle to ripping hot, wipe off excess butter, place the beef seasoned side down, top with the onions and smash flat, pressing down the edges; no parchment needed with the onions on.

Season the second side; scrape under the crust with a wallpaper scraper, working from several sides so the burger does not tear, and flip onion side down.

Top with cheese, set between the two grilled cheeses, overlapping the patties slightly for coverage; cut into triangles.