In 5-quart Dutch oven, heat 2 tablespoons of the oil over medium-high heat until hot. Cook onions, carrots, celery, garlic and salt in oil 5 to 6 minutes, stirring occasionally, until softened. Remove vegetable mixture from Dutch oven to small bowl.

In same Dutch oven, heat remaining 1 tablespoon oil over medium-high heat. Add mushrooms; cook 14 to 19 minutes, stirring occasionally, until mushrooms are tender and liquid has evaporated.

Stir in vegetable mixture, crushed tomatoes, tomato sauce, thyme, oregano and red pepper flakes; heat to simmering; reduce heat to medium-low. Continue cooking uncovered 15 to 20 minutes, stirring occasionally, until sauce is starting to thicken. Remove from heat; stir in soy sauce.

Meanwhile, cook fettuccine as directed on package; drain. Serve fettuccine with sauce. Garnish with shredded Parmesan cheese and basil.