Brown the beef: Heat a large pot over medium-high heat. Add the ground beef (1 1/2 pounds), salt (1 1/2 teaspoons), and pepper (1/2 teaspoon). Cook, breaking it into small pieces, until browned. Transfer to a plate with a slotted spoon.
Sauté the vegetables: Drain all but 2 tablespoons of fat from the pot and reduce heat to medium. Add onion (1 1/2 cups), bell pepper (1), and garlic (1 tablespoon). Cook until softened and translucent, about 5–7 minutes.
Build the sauce: Return the beef to the pot. Stir in crushed tomatoes (1 can), tomato sauce (1 can), tomato paste (1 can), Italian seasoning (1 tablespoon), and sugar (1/2 teaspoon). Bring to a boil.
Simmer: Reduce heat and simmer uncovered for 1 hour, stirring occasionally, until thickened. Taste and adjust seasoning as needed.
Cook the pasta: Cook spaghetti (16 ounces) in well-salted water according to package directions. Drain.
Combine and serve: Toss pasta with sauce or serve sauce over the top. Garnish with parsley (2 tablespoons) and Parmesan.
Notes
1.Use 80/20 ground beef. The fat adds flavor and creates the base for sautéing the vegetables. Leaner beef will work but won’t be as rich. 2. Layered tomato flavor. Crushed tomatoes, tomato sauce, and tomato paste work together to create a balanced, full-bodied sauce.3. Simmer uncovered. This allows the sauce to thicken properly and develop deeper flavor.