Preheat the oven to 300 degrees; line a baking sheet with tin foil then coat with cooking spray. Halve the tomatoes, cut the onions and break up the head of garlic (KEEP SKINS ON SO THEY DON’T BURN). Spread the tomatoes, onions and garlic all over the lined baking sheet. Drizzle with 1 tablespoon of olive oil over the top, then sprinkle with crushed fennel seeds, oregano, and crushed red pepper flakes, as well as sea salt and freshly cracked pepper; to taste; toss to coat.
Place in the oven and roast for 60 minutes; or until vegetables are really soft and the tomatoes are still juicy. Remove from the oven and let cool.
Once they have cooled, carefully peel the skin off the cloves of garlic. Spoon the tomatoes, onions, garlic and juices into a small Dutch oven along with the tomato sauce then simmer for 2-3 hours, stirring occasionally. Using an immersion blender, blend the vegetables until smooth, making sure there are no chunks. Add the vinegar then taste. Add more sea salt and freshly cracked pepper, to taste. Add the fresh basil then mix until well combined. Side Note: If you desire a sweeter sauce, add a pinch of sugar. If you want a thinner sauce, add a little chicken or vegetable broth, to taste.
Cook desired pasta in salted water, per instructions. Drain. Serve sauce tossed with your pasta then top with fresh basil and shaved Parmesan. Enjoy.