This recipe is courtesy of Kickshaws Kitchen, and as with many recipes pertaining to one type of greens, it can be used with most greens (or a blend of mild swiss chard and spicier greens such as mustard greens).
2 bunches of swiss chard leaves, chopped (about 8 cups packed)
1 Tbsp Extra Virgin Olive Oil
1 Tbsp unsalted butter, plus more to grease baking dish
1 cup low-fat milk
2 Tbsp all-purpose flour
1/4 tsp fine sea salt
1/4 cup Parmesan cheese, divided (or non-dairy mozzarella style cheeses)
1 Tbsp dry whole wheat bread crumbs
1/4 tsp ground black pepper
Pre-heat oven to 350F
Place chard leaves in a saucepan with the 1 cup water and cook over medium heat until leaves are just tender, 3 to 4 minutes. Drain, reserving 1/4 cup of the cooking liquid. Set chard aside.
In the same saucepan, heat olive oil and butter over medium heat. When butter has melted, whisk in the flour until blended. Whisk constantly for 1 minute. Slowly whisk in the milk and reserved cooking liquid. Continue cooking and stirring until the sauce thickens, 3 to 5 minutes. Season with salt & pepper and stir in half of the grated cheese.
Stir in the cooked chard and transfer to a buttered 9x9-inch baking dish. Sprinkle with the remaining cheese and breadcrumbs. Bake until hot and bubbling, about 20 minutes. Serve immediately.