Step 1

Pour the tomatoes and their juices into a large bowl and break them up with your hands.  Set aside.

Step 2

Heat the oil in a large shallow pot or skillet set over medium heat.  Add the onions and sauté until tender and soft, about 2-3 minutes.  Add the garlic, pepper flakes, oregano, and fennel and stir until fragrant, about 30 seconds.

Step 3

Add the tomatoes, salt, and pepper.  Bring to a boil, stirring frequently, then immediately reduce the heat to low. Add the fresh basil sprig, immersing it into the sauce.

Step 4

Simmer the sauce, uncovered, for 25-30 minutes until thickened.  With tongs or a fork, remove and discard the basil sprig. Transfer the sauce from the heat and stir in the chopped fresh parsley.

Step 5

Serve with your favorite recipes.