Cook pasta according to package directions, omitting salt and fat; drain.
Heat oil in a large skillet over medium-high heat. Add onion to pan; sauté 4 minutes or until tender. Add garlic; sauté 1 minute. Stir in oregano, celery salt, red pepper, black pepper, and saffron, if desired. Crumble beef into pan; cook 5 minutes or until beef is browned, stirring to crumble. Stir in marinara sauce, olives, sherry, capers, and 3 tablespoons parsley. Bring to a boil; reduce heat, and simmer 15 minutes.
Add spaghetti to sauce mixture. Cook 2 minutes or until thoroughly heated. Sprinkle with remaining 1 tablespoon parsley.
This recipe originally ran in Cooking Light December, 2009 and was updated for the November, 2012 25th anniversary issue.