Joshua’s Perfect Burger

Method

1. Caramelize the diced onion slowly in the butter with a pinch of salt, 20–25 minutes, adding a splash of water if it browns too fast. Cool completely.
2. Stir the rest of the sauce ingredients together, then fold in the cooled onion.
3. Butter the cut sides of the buns and toast them on a griddle or cast iron pan over medium heat until golden, 2–3 minutes.
4. Turn the heat to medium-high. Add two beef balls well apart, press a small ball of sliced onion onto each, and smash to ⅛ in thick. Season.
5. Cook about 90 seconds until deeply browned, scrape up firmly and flip in place. Add a slice of cheese and cook about 1 minute more.
6. Stack two patties per burger. Sauce both buns, lay three pickle planks on the bottom, add the double patty and close.