Step 1

Preheat oven to 350 degrees F. Lightly coat a 2-quart square baking dish with nonstick cooking spray; set aside. Cook jumbo shells according to package directions; drain. Rinse with cold water; drain again. Set aside.

Step 2

Meanwhile, in a medium skillet cook ground beef until brown, using a wooden spoon to break up meat as it cooks. Drain off fat. Set meat aside.

Step 3

In a large nonstick skillet, heat olive oil over medium heat. Add mushrooms, onion, carrot, celery, garlic, and Italian seasoning; cook for 6 to 8 minutes or until tender, stirring frequently. Add diced tomatoes and salt. Cook and stir for 2 minutes more. Remove from heat; cool slightly.

Step 4

Spoon the tomato mixture into a blender or food processor; cover and blend or process until nearly smooth. Set aside 3/4 cup of the pureed tomato mixture. Return the remaining pureed tomato mixture to the skillet. Stir cooked meat into tomato mixture in skillet. Spoon a rounded tablespoon of the meat mixture into each pasta shell.

Step 5

Arrange filled pasta shells in prepared baking dish. Spoon the reserved 3/4 cup pureed tomato mixture over the shells.

Step 6

Cover with foil; bake for 20 minutes. Sprinkle with cheese and fresh tomato. Bake about 5 minutes more or until heated through and cheese is melted. If desired, sprinkle with basil.