Bao zai fan (煲仔饭, literally small pot rice) is the Cantonese clay pot rice preparation — individual portions of rice cooked in a small unglazed clay pot over a charcoal or gas flame, the rice absorbing the flavours of toppings (typically chicken and Chinese sausage, or preserved meats) while the rice develops a crispy, toasted crust at the base of the pot. The crust (guo ba, 锅巴) is the most prized element — scraped from the bottom of the pot and eaten as a textural contrast to the soft rice above.
The clay pot: An unglazed clay pot with a tight-fitting lid is essential — the porous clay absorbs and distributes heat differently from metal, and the moisture regulation it provides is irreplaceable in achieving the crispy bottom without burning. The rice: Use medium-grain white rice, washed and soaked 30 minutes. The water ratio for clay pot rice is slightly higher than normal — approximately 1:1.3 (rice:water) because some moisture is absorbed by the clay. The cooking sequence: Add water and rice to the pot. Place over medium heat. Bring to a boil (5 minutes). Reduce heat to the lowest possible setting. Place the toppings on the surface of the partially cooked rice. Cover and cook a further 10 minutes. In the final 2-3 minutes, increase heat briefly to medium to develop the crispy base. The finish: Drizzle with a sauce of soy sauce, oyster sauce, sesame oil, and sugar mixed together.
Using a glazed clay pot: Glazed clay does not breathe in the same way. Using a metal pot: The rice becomes steamed rather than clay-pot cooked.
Fuchsia Dunlop, Land of Fish and Rice (2016); Eileen Yin-Fei Lo, Mastering the Art of Chinese Cooking (2009)