1 tbsp olive oil
3 tbsp unsalted butter
1 cup fresh bread crumbs
3 oz gruyère cheese, grated (1 cup)
1 clove garlic, finely chopped
1 tbsp assorted fresh herbs (chives, tarragon, and flat-leaf parsley, par example), finely chopped
1/8 tsp nutmeg, grated
1/2 cup milk, cream, or dairy-free substitute
1 tbsp all-purpose flour (to thicken, this could be replaced with gluten-free alt)
1 medium onion, finely chopped
3 bunches swiss chard, leaves and stems separated and both cut into 1-inch pieces
toss bread crumbs with oil, garlic, herbs, and salt and pepper (to taste – I like quite a bit of pepper with gratineed greens) in a bowl. preheat oven to 400°f and bring a large pot of water to boil. when boiling, add chopped chard stems, torn chard and spinach. cook until mostly done, then blanch in cold water. squeeze as much water out as is manageable and roughly chop.
in a large skillet, add butter, and saute onion over med-low heat, until soft and translucent. sift flour into the same pan, stirring to combine with butter, and continue stirring until a light roux is formed [then add milk – thanks dt]. add nutmeg, salt and pepper to taste, and remove from heat. toss greens with cream sauce and transfer to a buttered 12-inch oval gratin or 2-quart shallow baking dish, spreading evenly. top greens with cheese and bread crumbs and bake until bubbling and crumbs are golden, 20 minutes or so.