Preheat oven to 350°. Spray a 3-quart baking dish with cooking spray.
Cut top off each tomato ½ inch from stem; reserve tops. Using a spoon, scoop tomato pulp into the work bowl of a food processor; purée until smooth. Place tomato shells in prepared pan.
In a large nonstick skillet, cook sausage, onion, garlic, salt, and pepper over medium heat, stirring occasionally, until sausage is browned, about 10 minutes. Add tomato purée; bring to a boil. Remove from heat.
Stir ¾ cup cheese, bread crumbs, parsley, walnuts, and lemon zest and juice into sausage mixture. Divide mixture among tomato shells; top with remaining ½ cup cheese. Brush oil onto tomato tops; place tops on tomatoes.
Bake until filling is hot and bubbly and tomatoes are tender, about 20 minutes. Garnish with parsley, if desired.
Notes
For best results, choose tomatoes that are ripe but still slightly firm.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/sausage-stuffed-tomatoes-recipes/