Heat the oil in a stock pot over medium high heat. Add the chopped red onion and fry until slightly golden. Add the tomatoes, carrots and garlic and bring to a simmer over medium heat. Reduce heat to low and simmer, covered, for 1 hour. After an hour, stir in the 10 large basil leaves and salt and continue to simmer, uncovered, for another 15 minutes.
During these last 15 minutes you can cook your pasta according to the package instructions. Drain and set aside.
After the 15 minutes, remove and discard the garlic clove from your sauce. Working in batches in a standing blender, or using an immersion blender, puree the sauce until smooth. (I find that a standing blender produces a much creamier and velvety sauce).
Once smooth, return the sauce to the pot. Taste the sauce, and add the sugar if you find it to be too acidic or more salt as desired.
Toss your pasta in the sauce and serve immediately with some extra basil leaves for garnish and some grated parmesan on the side.
I have made this with spaghetti as that is my kids’ favorite. However, Benedetta has advised that with a yummy sauce like this, it is best to serve it with a hole-shaped pasta like mezzi rigatoni or normal rigatoni that will capture and hold all that lovely sauce inside it. She’s the Italian so probably best to follow her lead…