Meanwhile, in a large skillet over medium heat, heat oil. Add onions and cook until soft about 5 minutes. Stir in garlic and cook about 1 minute more. Add ground beef, season with salt, pepper, and Italian seasoning, and cook until no longer pink, about 8 minutes. Drain fat in a bowl lined with paper towels and return to pan (optional). Pour in crushed tomatoes and basil and simmer until slightly reduced, about 10 minutes. Season with more salt and pepper to taste.