First cut the sweet potatoes, potatoes and carrots into cubes. Cut an onion into rings and mix well with the vegetables, rosemary and 50 ml of olive oil. Then in a fire-proof pan at 180 degrees in the oven. Mix after 20 minutes and leave in the oven for another 15 minutes. If necessary, set the last 15 minutes on the grill setting so that the vegetables get a little crispy - depending on how you like them. If you prefer it softer, just leave it in the oven until the desired cooking level is reached.
Sear the fish briefly on both sides and set aside. Now heat the rest of the olive oil (not too much). Add the diced garlic and diced onions. Let the whole thing stand briefly. Then add the chillies, lemon juice and fish sauce and add the fish again. Let the dish steep for 7 - 8 minutes (not too hot, the oil should simmer slightly). Finally add the fresh coriander and mix.
The fish should now be nice and tender and have a great taste. The oil sauce tastes great with the Mediterranean vegetables.