In a large dutch oven, heat Olive Oil (2 tablespoon) over medium heat. Add Carrot (3), Celery (4 stalk), Onion (1), Garlic (6 clove), Fennel Bulb (2), and Salt (1/2 teaspoon). Stir and cover with a lid. Reduce heat slightly, and let the vegetables cook.
Stir occasionally, until vegetables are tender and they take on a translucent quality, about 10-12 minutes. Remove from heat.
With clean hands, remove tomatoes one at a time from the Whole Peeled Tomatoes (3 can) and squeeze them over the pot to release their juices and squish them. Add them to the pot along with the remaining tomato puree and stir.
Add Bay Leaf (2), Crushed Red Pepper Flakes (1/4 teaspoon), Kosher Salt (1 teaspoon), and freshly ground Ground Black Pepper (1/2 teaspoon). Stir to combine.
Return the pot to medium high heat with the cover offset. When the mixture starts to bubble, reduce heat to medium low. Cover and simmer for about an hour, stirring occasionally. Remove from heat.
Using a food processor or a blender and working in batches, process the sauce until smooth.
It's now ready for your favorite recipe, or can be canned or frozen in batches as needed.