4 tablespoons unsalted butter
1 large onion, finely shopped
1 pound collard greens, stems and leaves shopped separately
1/4 cup milk
1/2 cup heavy cream
1/2 teaspoon salt
1/4 teaspoon freshly ground black pepper
2/3 cup fresh bread crumbs
1/2 cup grated Jarlsberg cheese
5 eggs, lightly beaten
Melt 1 tablespoon butter in a skillet over medium-low heat. Add onion and cook until transparent. Stir in the collards and cook, covered, until tender, about 3 minutes. Raise the heat to medium-high and remove the cover. Cook tossing constantly, until all the liquid has evaporated. Cool in a large bowl.
Preheat oven to 325°F. Melt the remaining butter and add it, plus all the remaining ingredients, to the greens mixture. Mix well and pour into a buttered soufflé dish. Place the dish in a roasting pan and pour boiling water in the pan to half the depth of the dish. Bake until a knife comes out clean, about 45 minutes. Remove the dish from the pan and let stand 10 minutes. Run a knife around the edges and carefully invert onto a shallow serving platter.