Cá chiên nước mắm is fried fish finished with a glossy fish sauce caramel, and it's a staple of southern Vietnamese home cooking and cơm bình dân (everyday rice) eateries. The fish is fried until crisp, then the garlic, chilli, fish sauce and sugar bubble down into a sticky, salty-sweet glaze.
It's served with rice and something fresh, such as sliced cucumber or herbs, to cut through the richness.
Adaptation note: in Vietnam it's usually made with a whole fish, often red tilapia (cá diêu hồng). We use skin-on fillets such as barramundi or snapper so it cooks quickly and evenly in a frying pan.