Place the onion, carrots, zucchini, and red bell pepper into the bowl of a food processor. Blend the mixture until finely chopped and slightly pulpy in texture.
Heat the oil in a Dutch oven over medium-high heat. Add the blended vegetable mixture, cooking it for approximately 10 minutes. Stir occasionally, allowing it to become lightly browned and aromatic.
Shift the sautéed vegetables to the edges of the pot. Introduce the ground beef to the center, breaking it into small pieces as it browns. Cook until the beef loses its pink color, which should take about 3 minutes.
Incorporate the minced garlic, tomato paste, oregano, basil, salt, sugar, and black pepper. Stir and cook for 30 seconds, ensuring the spices release their full aroma.
Add the diced tomatoes, tomato sauce, and water to the pot. Stir thoroughly to blend all components. Reduce the heat to medium, allowing the sauce to simmer for 15–20 minutes until the flavors meld and the consistency thickens.
Serve the sauce over a cooked pasta of your choice. Enhance the dish by garnishing with freshly grated Parmesan cheese and sprigs of basil.