Put similar quantities of hake fillets on two sheets of baking parchment or aluminium foil. Put the thinly sliced lemon, the courgette and carrots, cut into sticks, on the fillets and sprinkle the oil on top. Seal the pouches well.
Place the pouches on a baking tray and bake for 10 minutes. Remove.
Open the papillote and remove the lemon slices. Serve.