Bring a large pot of salted water to a boil and cook the spaghetti until al dente. Drain and set aside.
Heat the olive oil in a large skillet or sauté pan over medium heat.
Add the ground beef and cook, breaking it up as it browns.
Add the chopped onion and red bell pepper, then cook until softened.
Stir in the minced garlic and cook briefly until fragrant.
Add the tomato paste and stir well.
Pour in the tomato sauce and water, then mix to combine.
Season with salt, black pepper, dried oregano, and paprika if using.
Simmer until the sauce thickens and the flavors come together.
Stir in the chopped parsley.
Spoon the meat sauce over the cooked spaghetti and top with Parmesan for serving.
