Cut the potatoes into 1/2-inch wide strips.
Put the strips in a large bowl with warm water and soak for 20 minutes.
Pour the oil into a Dutch oven and heat over medium-high until it reaches 350°F
Line a rimmed baking sheet with paper towels and place a wire rack on top.
Drain the potatoes and dry them thoroughly with paper towels. Add half of the dried potatoes to the hot oil and cook, stirring often, for about 3 minutes until they soften slightly.
Transfer the potatoes to the wire rack to drain. Repeat with the remaining potatoes. Keep the oil at 350°F for the final fry.
Divide the ground chuck into 4 portions and flatten them into 1/4-inch thick patties.
Heat a large skillet over medium-high heat.
Add the patties and cook without disturbing for 2 to 3 minutes until a brown crust forms around the edges.
Flip the patties, press down with a spatula to flatten, and cook for another 2 minutes.
Flip again, press down once more, and top each patty with a slice of cheese. Cook for 1 more minute
While the patties cook, spread mustard and ketchup on the bottom halves of the buns.
Drizzle hot sauce on the top halves of the buns, then spread mayonnaise over the top and add lettuce, tomato slices, pickles, and onions.
Place one patty on top of another so the cheese sides touch.
Place each stacked patty onto a top bun and cover with a bottom bun, condiment-side down, also remeber to wrap the burgers in foil.
Return the fries to the hot oil and cook until golden brown, 3 to 4 minutes and drain on paper towels and sprinkle with salt.
Serve immediately with the burgers.