Run your fingers over the flesh side of the fish and, using tweezers, remove any pin bones still in the fillets.
Slowly heat a large heavy frying pan until the heat rises from the surface.
Meanwhile, put the paneer, herbs, lemon zest, garlic and some salt and pepper in a small bowl and mix. Spread the mixture evenly on the flesh side of two of the fillets.
Place the remaining fillets on top, flesh side down, to make two parcels. Tie pieces of dhaaga around both parcels to secure them, then brush lightly with oil on each side.
Transfer the fish to the frying pan and cook for 8-10 minutes on each side, until cooked and pale pink throughout. Remove the fish to a plate and let rest for 5 minutes, then remove the string and serve with boiled new potatoes and carrots.
You can also use a small whole salmon in place of trout. For a whole salmon, simply double the filling mixture and cook the fish for 15-20 minutes on each side, then leave to rest for 10 minutes before serving.