Fold a large sheet of foil or baking paper in half and tightly fold one side to seal. Grate the lemon zest and mix with the couscous, pine nuts, courgette and dill. Season well, then tip into the open bag.
Cut the lemon in half, then cut 2 thin slices from one half. Juice the other half and add the juice to the stock.
Lay the haddock on top of the couscous, top with the lemon slices, then carefully pour over the lemony stock. Fold the remaining open sides tightly.
Bake for 20-25 mins, depending on how thick your fish is, until the fish is cooked and couscous is fluffy.
