1 cup whole-milk ricotta cheese
1/2 cup grated Parmesan cheese
Preheat the oven to 375°F. Grease a 9x13-inch or equivalent casserole dish with butter. Scatter the bread over the base of the dish. Whisk together the milk and eggs in a large bowl, and pour the milk mixture over the bread to soak while you cook the vegetables.
Melt the tablespoon of butter in a large skillet over medium heat. Add the onions and cook, stirring often, until soft, about 5 minutes. Add the Swiss chard stems and continue to cook and stir until the stems are tender, 2 to 3 minutes. Add the Swiss chard leaves and water to the skillet. Bring to a boil, cover, and lower the heat. Cook, lifting the lid to stir the greens once or twice, until the greens are wilted but still bright green, 2 to 3 minutes. Taste and season with salt if needed.
Fold the sausage, ricotta, and half the Parmesan into the soaked bread. Transfer the greens to the dish as well, leaving any liquid in the skillet. Nestle the greens into the bread mixture. Top with the remaining Parmesan and bake, uncovered, until the center doesn't weep when pierced with a knife, about 1 hour.
Recipe Notes
- A note on salt and pepper: The flavor of this pudding varies greatly depending on the flavor of the bread, sausage, and ricotta. I find it doesn't usually need any additional salt besides what's in the components, but if one of your components is particularly bland, you might want to add a bit. Serve with salt and pepper alongside, so each eater can do as they please.