First, wash well if it's homegrown chard. There can be a lot of dirt clinging to the leaves.
Cut the stalks off the leaves and set the leaves aside. Cut the stalks into 1/2" pieces.
Whisk the flour into the water and bring to a boil. Add the stems, lemon juice, and a bit of salt. Cook for 20-30 minutes, until tender.
Bring a large pot of water to boil for the leaves. My leaves were quite large so I cut them in half before dropping them in the water. Cook them about 10-15 minutes, drain, and chop, then toss with butter and salt to taste.
Place stems and leaves into a shallow baking dish along with the cream. Mix the bread crumbs and cheese together, then sprinkle across the top. Bake at 425 for 15 minutes.
Chard Gratin https://cheapcooking.com/gratin-of-swiss-chard/ August 15, 2006