Cook pasta according to package directions, omitting salt and fat.
Drain.
Heat marinara sauce in a large saucepan over medium heat.
Add salt, pepper, and spinach, stirring until blended; cook for 10 minutes, stirring occasionally.
Remove from heat; stir in cooked pasta.
Spoon half of pasta mixture into a 13 x 9-inch baking dish coated with cooking spray.
Combine sour cream, smoked cheese, and basil; spread over pasta mixture in dish. Spoon the remaining pasta mixture over sour cream mixture; sprinkle evenly with Parmigiano-Reggiano.