Cut the bell peppers in half lengthwise and remove the stems and seeds. Mince the onion.

In a bowl, mix the breadcrumbs, milk, and beaten egg to soften. Add the ground meat, minced onion, salt, and pepper, then mix well to form the meat filling. Divide into 12 equal portions.

Place the bell peppers cut-side up and dust the inside with flour using a sieve. Fill each pepper evenly with the meat filling.

Heat vegetable oil in a frying pan over medium heat. Place the stuffed peppers meat-side down and cook until browned. Flip them, cover with a lid, and steam on low heat for 4–5 minutes until the meat is cooked through.