It's best harvested before the leaves got too big; take a couple from each plant and leave it to grow on and produce more leaves and stems.
You can chop teh bay/small leaves into salad; bigger leaves are removed from the stalks and treatd like spinach - steamed/wilted, then add butter, nutmeg, etc. Good in quiches too. The stems can be steamed and eaten as a speparate veg, or along with the leaves, or can be chopped and added to soups, quiches, casseroles, etc.
I grow the Bright Lights/Jacob's Coat chard every year. They will get quite big if you grow them on to seed.
Excellent productive vegetable that looks good int he garden and will stand the winter.
Another recipe if they get too big is one from Alister Little, chard lasagine.
Basically chard in layers (cooked) with the white sauce and parmasan, then pasta, repeat.
Bloody great. I now chop the chard hard down to the ground, that way you prelong the bolting , and get smaller leaves
It's not easy being Cheezy
So you know how great Salsify is as a veg, what about Cavero Nero,great leaves all through the winter , then in Spring sprouting broccolli like flowers! Takes up half as much room as broccolli