Bosnian Pljeskavica in a Bun

Method

1. In a large bowl, mix ground beef, pork, onion, egg, olive oil, salt, and pepper until well combined.
2. Form the mixture into 4 equal-sized patties.
3. Heat a skillet over medium heat and cook the patties for 4-5 minutes on each side until browned and cooked through.
4. Toast the buns and assemble them with the patties, then add ketchup, mustard, lettuce, tomato, and onion slices.
5. Check that the ground meat reaches 71°C (160°F) throughout before serving.