In a large pot or Dutch oven over medium-high heat, brown the ground beef, breaking it up as it cooks, until no longer pink.
Add the diced onion and diced green bell pepper to the pot and sauté with the beef until the vegetables are softened, about 4–5 minutes.
Stir in the tomato sauce, stewed tomatoes (with their juices), water, and the bouillon cubes until the cubes dissolve.
Add dried basil, dried oregano, chili powder, parsley flakes, garlic powder, black pepper, and Accent seasoning (if using). Stir to combine.
Bring the sauce to a gentle simmer, reduce the heat to low, and simmer uncovered for 20 minutes to develop the flavors.
Stir in the grated Parmesan cheese, taste, and add a pinch of salt and/or a pinch of sugar if desired to balance acidity.
Meanwhile, bring about 4 quarts of water to a boil in a large pot. Add the spaghetti and stir until the water returns to a boil.
Reduce heat to maintain a gentle boil and cook the spaghetti 8–9 minutes, or until it reaches your desired tenderness, then drain in a colander.
Serve the drained spaghetti with the meat sauce spooned over or alongside the noodles.
