The minced meat, egg and chopped onions are fried on a frying pan and then placed into the cavity of a baguette halved lengthwise. The whole baguette is then briefly pan-fried on the frying pan and then served after being cut into several portions. A variant is to place the minced meat, onions and sauce inside the baguette, then baguette dipped into beaten egg, and the whole then pan-fried on the frying pan.
In Malaysia, sardines and other variations have been added.
Roti is the Hindi, Urdu and Malay word for bread, and more generally for any bread-based or bread-like food, including sandwiches and pancakes. The origin of john in the name is allegedly due to the Western origin of the baguette and the tomato sauce used in the dish.
The dish is considered part of Malay cuisine. Multiple theories about its origin exist, the earliest tracing it to food hawkers in Singapore in the 1960s or 1970s. The dish spread to Malaysia via Tanjung Kling, Malacca, as early as 1976–1978. (wikipedia)