As you scrub, peel and cut up each root, drop it into a saucepan of water, to which you have added the lemon juice.
Drain. You can use some of the cooking liquid for the sauce.
Melt half the butter, stir in the flour, and gradually add the liquid, stirring until you have a smooth paste. Simmer for 10 minutes, and then season and stir in half the cheese, if using it.
Combine the cooked salsify and sauce, and spoon into an ovenproof dish. Scatter the rest of the cheese on top, dot with the remaining butter, and sprinkle on the breadcrumbs. Bake at 180-200°C/350-400°F/gas mark 4-6 for 15 to 30 minutes.
© 2000 Frances Bissell. All rights reserved.