Fill a large pot with water, salt it generously, and bring to a rolling boil. Add spaghetti and cook according to package instructions until al dente. Before draining, scoop out and reserve 1 cup of pasta water. Drain the pasta.

While the pasta cooks, heat 2 tablespoons of olive oil in a large skillet over medium heat.

Add the chopped onion and sauté until translucent, about 4 to 5 minutes. Stir in the minced garlic and cook for 30 to 60 seconds until fragrant.

Add the ground beef to the skillet. Break it into small pieces with a spoon and cook until evenly browned. If there is excess fat, drain it from the pan.

Stir in the canned tomatoes and tomato paste. Season with salt, black pepper, and the teaspoon of Italian seasoning. Mix until the paste is fully incorporated.

Reduce the heat to low and let the sauce simmer gently, uncovered, for 20 to 30 minutes. Stir occasionally. If the sauce becomes too thick, add a few tablespoons of the reserved pasta water to loosen it. Taste and adjust seasoning.

Either toss the drained spaghetti with a portion of the sauce so every strand is coated, or plate the pasta and spoon the meat sauce on top. Finish with a generous grating of Parmesan cheese.