Step 1

In a large heavy-bottomed pot set over medium heat, render the bacon. Add the butter and onions. Cook over low heat, stirring occasionally, 1½ hours. Cooking the onions this slowly will let them caramelize naturally in their sugars.

Step 2

Add the vinegar and sugar to the pot and cook for 15 minutes, then remove from the heat. Let cool and place in a container and store in the refrigerator. (When you make the P&L Burgers, you can warm some of this jam in a pan.)

Step 3

Place cast-iron skillet over medium heat 5 minutes before cooking the patties.

Step 4

Roll 6-ounce (170 g) burger balls from the brisket and pat them into flat, thick patties, about 1 inch (2.5 cm) thick. Season the patties with salt and pepper.

Step 5

In a bowl, combine the pickles and mayonnaise; set aside.

Step 6

Place three patties in the skillet (with no oil). The fat will render and you will have a juicier burger from the natural fat inside the patty. Cook for 4 minutes on one side, then flip.

Step 7

Top each patty with the jam and then put 2 slices of cheese per patty on top. Pour 2 tablespoons water into the skillet, covering it immediately so the burgers can steam. Remove the lid after 45 seconds. The cheese should be fully melted.

Step 8

Butter the buns and place them face down in another skillet over medium high heat so they get nice and toasty.

Step 9

Spoon the pickle mayo on the bottom buns, then add a good pile of the lettuce. Add the cheesy beef patties, cover with more of the pickle mayo,then add bun tops.