Special equipment: a deep-fry thermometer and 18-by-13-inch rimmed baking sheet
For the sauce: Stir together the ketchup, mayonnaise, mustard and steak sauce in a medium bowl, and set aside.
For the fried pickles: Add the breadcrumbs, onion powder, paprika, cayenne and salt to a large re-sealable bag, and shake to combine.
Add the pickle chips to the bag, shake to coat. Remove them from the bag and spread on a baking sheet.
Heat a cast-iron skillet with 1 inch of oil to 350 degrees F.
Add the pickle chips to the skillet in batches and fry for about 30 seconds per side or until golden brown.
Remove the pickle chips to a paper-towel-lined baking sheet and reserve.
For the cheeseburgers: Preheat the oven to 425 degrees F, and prepare a grill for medium-high heat. Line a rimmed baking sheet with parchment paper.
Arrange the pancetta on the prepared baking sheet in a single layer. Bake the pancetta until golden brown and crisp, about 10 minutes. Transfer to a paper-towel-lined plate to drain.
Add 2 teaspoons salt and 1/2 teaspoon pepper to the beef in a medium bowl and mix well with your hands. Press the meat in one thin layer on a 18-by-13-inch rimmed baking sheet.
Use a knife or pizza cutter to divide the meat into 12 square patties.
Grill the patties on one side until halfway cooked, about 3 minutes.
Flip the patties, top with a slice of cheese and continue cooking until cooked through and the cheese begins to melt, 1 to 2 minutes more.
Build each burger in a split bun as follows: patty, schmear of special sauce, slice of pancetta, 2 pickles and repeat. Top with the tomato and lettuce.