1. Combine the butter, paprika and garlic in a small saucepan and heat over the coals, stirring to prevent the garlic from burning.
2. Pat the snoek dry with paper towels. Brush the skin with a little melted butter or olive oil to prevent it sticking and open up the fish like a book.
3. Place the fish, skin-side down, on a hinged grid lined with foil. Using the rosemary sprigs, brush the flesh side with the paprika garlic butter.