Preheat oven to 350 degrees F (175 degrees C). Butter one 8x8x2 inch glass baking dish and set aside.
Cover roasting rack with aluminum foil and place in roasting pan. Place crown roast, bone ends up, on foil lined rack. Bake at 350 degrees F (175 degrees C) for 1 hour.
Prepare the stuffing by melting 2 tablespoons butter in a large skillet over medium-high heat. Add sausage and onion; cook until sausage is crumbled and fully cooked. Remove from heat. Stir in bread crumbs, chestnuts, chicken broth, parsley, sage, thyme, salt and pepper. Mix well.
Boil 2 cups broth and vermouth in large saucepan until reduced by half.
Place the bacon in a large, deep skillet. Cook over medium high heat until evenly brown. Drain, crumble, and set aside.
In the same skillet over medium high heat, melt 3 tablespoons butter. Add flour; mix and cook until golden brown. Add broth mixture and boil until slightly thickened, about 5 minutes. Add bacon; season with salt and pepper.
Remove pork from oven and fill cavity with stuffing; cover stuffing with foil. Transfer remaining stuffing to prepared baking dish.
Place roast and extra stuffing in oven. Bake until thermometer inserted into center of pork registers 145 degrees F (63 degrees C), about 1 hour. Baste roast occasionally with drippings. Transfer roast to serving platter and cover.
Carve pork between the bones into chops. Serve with stuffing and gravy.
