1. Preheat the oven to 325°F.

2. Melt half of the butter in a skillet over medium heat. Add the chopped onions and cook, partially covered, until tender and lightly colored, about 25 minutes. Transfer the onions and butter to a large mixing bowl.

3. Melt the remaining butter in the same skillet. Add the apple chunks and cook over high heat until lightly colored but not mushy. Transfer the apples and butter to the mixing bowl.

4. Crumble the sausage into the skillet and cook over medium heat, stirring, until lightly browned. With a slotted spoon, transfer the sausage to the mixing bowl and reserve the rendered fat.

5. Add the remaining ingredients to the ingredients in the mixing bowl and combine gently. Cool completely before stuffing the bird; refrigerate if not used promptly.

6. If you do not wish actually to stuff the bird (goose or duck, for example, can make the stuffing greasy), spoon it into a casserole. Cover the casserole and set into a large pan. Pour hot water around the casserole to come halfway up the sides. Bake for 30 to 45 minutes, basting occasionally with the cooking juices from the bird or with the reserved sausage fat if necessary.