Heat the cast iron skillet over medium-high heat and pan-fry the diced russet potatoes in oil for 12–15 minutes, stirring occasionally, until golden and crispy. Season with salt and pepper to taste, then set the potatoes aside.

In the same skillet, brown the ground beef with the diced onion and diced green bell pepper over medium-high heat, stirring until the beef is cooked through. Drain excess fat, then add the minced garlic and stir for about 30 seconds.

Stir in the ketchup, yellow mustard, brown sugar, Worcestershire sauce, and apple cider vinegar, then simmer for 5 minutes until the sauce thickens. Keep the heat steady so the mixture reduces and coats the meat.

Return the crispy potatoes to the skillet and toss until the potatoes are coated with the sloppy joe meat sauce. Spread everything into an even layer for better melting.

Sprinkle shredded cheddar cheese over the top, cover the skillet, and heat for 2 minutes until the cheddar is melted and bubbly. Turn off the heat and let it rest briefly so the sauce clings to the potatoes.

Serve hot with dill pickles and diced white onion on top. Add a few extra pickles if you like the tangy-sweet flavor to pop.