Bring a large pot of salted water to a boil. Cook the pasta according to the package directions until al dente. Drain and set aside.
Heat the olive oil in a large skillet over medium-high heat. Add the onions and cook for 5 minutes or until soft and translucent. Add the garlic and cook for 1 minute or until fragrant. Add the ground beef and cook until the beef is no longer pink. Spoon out excess fat from the skillet.
In a small bowl, whisk together the beef broth and cornstarch. Add it to the skillet and stir. Add the crushed tomatoes, Italian seasoning, oregano, paprika, and red pepper flakes to the pan and stir until well combined.
Pour the cooked pasta into the skillet along with the half-and-half and sour cream. Stir until combined. Add the shredded cheddar cheese and stir to allow it to melt completely into the sauce.
Season the pasta with salt and pepper to taste and top with chopped parsley. Serve warm.
Notes
You can use heavy cream instead of half-and-half for an even creamier dish.