Place a large skillet over medium-high heat. Add the ground beef (and the butter or oil, if using). Cook, breaking the meat into small crumbles with a wooden spoon or spatula, until browned and no pink remains, about 5–7 minutes.

If there is a lot of fat in the skillet, carefully tilt the pan and spoon off the excess grease, or drain into a heat-safe container. Return the meat to the skillet.

Pour the can of sloppy joe sauce over the cooked beef. Stir well so all the meat is evenly coated and the mixture looks thick and glossy.

Reduce the heat to low and let the mixture simmer for about 5 minutes, stirring occasionally, until the sauce thickens slightly and clings to the meat. Season with salt and black pepper to taste, if desired.

While the filling simmers, warm the hamburger buns. Toast them cut-side down in a dry skillet for 1–2 minutes, or wrap in foil and warm in a 300°F (150°C) oven for 5–7 minutes. In a pinch, microwave for 10–15 seconds.

Spoon a generous amount of the sloppy joe mixture onto the bottom half of each bun. Add sliced pickles, shredded cheese, or coleslaw if using, then top with the other half of the bun. Serve warm.