In a large sauté pan over very low heat, add olive oil, and once hot add onions. Add a tiny sprinkle of salt to open the onions up just a bit. Cook them low and slow for a minimum of 30 minutes, giving them a stir every minute or so.
Add two cans of whole, peeled, San Marzano tomatoes and basil to the pan, and bring heat up just a touch. You'll want to slow cook the tomatoes,garlic and onions together for 2 hours over low heat so the flavors come together nicely.
Do a taste test and add salt and pepper accordingly. You may not need very much seasoning as the low and slow cooking method produces a lot of flavors. Remove from heat and place sauce in a Vitamix or similar blender (or you can use an immersion blender). Puree until smooth.
In a large pot boil salted water. Once boiling add your Barilla Red Lentil Rotini and cook until al dente. Strain and serve with your classic tomato sauce.