Prepare an oven pan. Using tin foil to line the pan works very well. Grease the tin foil with butter before placing the fish in the pan.
Sprinkle the snoek with lemon and rosemary spice and lemon juice.
Cover the fish completely with the grated parmesan cheese and then the crumbs.
Add dollops of butter.
Sprinkle sparingly with dried dill.
Place in oven on middle rack and grill for 20 to 30 minutes, depending on the size of the fish.
For the Sweet Potato Sauce
While the fish is in the oven, clean the sweet potatoes and cut in slices.
Add them to a saucepan and cook on medium heat in a little water until tender.
Using a smaller saucepan, bring the orange juice to boil, reduce the heat and add the butter, corn flour and whisk until smooth. When thick and ready, taste and add the sweetener or sugar to taste.
Add the sauce to the cooked sweet potatoes and set aside until ready to serve.