Cut small slice off bottom of each tomato so they stand upright. Core tomatoes. Scoop out and reserve 1 cup of tomato pulp. Invert tomato shells onto large plate lined with paper toweling to drain.
Bring the chicken broth to simmering in a medium-size saucepan over medium heat. Reduce heat to very low to maintain a simmer; cover until ready to use.
Remove casing from sausage and discard; break meat into pieces. Cook sausage in large saucepan over medium heat until browned, about 7 minutes, breaking up any large pieces with fork. With slotted spoon, transfer sausage to plate.
Cook onion in the drippings in the saucepan over medium-low heat until very tender, about 8 minutes. Stir in the reserved tomato pulp; cook over medium heat, stirring occasionally, until the liquid is reduced by half, about 5 minutes.
Add rice to saucepan, stirring until rice is well coated. Add 1/2 cup of the simmering chicken broth; cook over medium-high heat, stirring constantly, until broth is absorbed. Continue adding broth, 1/2 cup at a time, stirring constantly, making sure each portion of broth is completely absorbed before adding the next. This should take about 20 minutes total; the rice should be firm to the bite. Stir in the cooked sausage, 4 tablespoons of the grated Parmesan cheese and the pepper.
Heat oven to 400 degrees F. Grease 14 x 11 x 3-inch glass baking dish. Sprinkle inside of tomato shells with salt. Stuff tomato shells with rice mixture, mounding it slightly on top. Place stuffed tomatoes into baking dish. Cover baking dish loosely with aluminum foil.
Bake in 400 degree F oven for 15 to 20 minutes or until tomatoes are tender, but still intact, and filling is hot. Top with remaining 2 tablespoons Parmesan cheese and chopped parsley. Serve immediately. Makes 6 servings.