Preheat the oven to 375 degrees F and butter a shallow 3-quart baking dish. Melt 6 tablespoons butter in a large nonstick skillet over medium-high heat. Add the sausage and cook, stirring and breaking up the meat with a wooden spoon, until lightly browned and no longer pink, about 6 minutes.
Add the celery and onions and cook, stirring occasionally, until softened, about 5 minutes. Stir in the sage. Add the broth, 1 teaspoon salt and a few grinds of pepper; bring to a simmer, then remove from the heat.
Whisk the eggs in a large bowl. Add the parsley, bread cubes and sausage-broth mixture and stir until combined. Transfer the stuffing to the prepared baking dish. Cut the remaining 2 tablespoons butter into small cubes and scatter evenly over the stuffing. Cover with foil and bake 30 minutes, then uncover and bake until golden, 20 to 30 more minutes.
Photograph by Ryan Dausch