Heat olive oil in a large heavy-bottomed pot or Dutch oven over medium-high heat. Add the diced onion and bell pepper and cook, stirring occasionally, for 5 to 6 minutes until softened and beginning to caramelize at the edges.

Add the minced garlic and cook for 1 minute until fragrant, stirring constantly to prevent burning.

Add the ground beef and break it apart with a wooden spoon. Cook over medium-high heat, stirring and breaking up the meat, for 7 to 8 minutes until fully browned with no pink remaining. Drain excess fat if needed, leaving about 1 tablespoon in the pot for flavor.

Stir in the tomato paste and cook for 1 to 2 minutes, stirring constantly, until it darkens slightly and coats the meat.

Add the ketchup, Worcestershire sauce, apple cider vinegar, brown sugar, smoked paprika, mustard powder, salt, black pepper, cayenne (if using), and beef broth. Stir everything together until fully combined.

Reduce heat to medium-low and simmer the filling uncovered for 12 to 15 minutes, stirring occasionally, until the sauce thickens and becomes glossy and deeply flavored. Taste and adjust salt, vinegar, or brown sugar as needed.

Remove from heat and allow to cool completely. Transfer to an airtight container or heavy-duty zip-lock bag and refrigerate for up to 3 days. The flavor improves overnight.

Set a cast iron Dutch oven or camp pot directly over the campfire grate over medium heat. Add the pre-made sloppy joe filling to the pot.

Stir the filling as it heats, warming it through for 10 to 15 minutes until it is piping hot throughout. If the filling has thickened too much in the fridge, add a splash of water or beef broth and stir to loosen.

While the filling heats, place the buns cut-side down on the fire grate and toast for 60 to 90 seconds until golden brown with slightly charred edges.

Spoon the hot sloppy joe filling generously onto the toasted buns. Top with shredded cheddar, pickle slices, and coleslaw if desired. Serve immediately and enjoy around the fire.