Begin with a large skillet over medium-high heat, cook ground beef and onion until no longer pink in the middle and onions are translucent. Drain grease.
Next add in the rest of the ingredients except for the half and half and cheese.
Bring to a boil. Turn down heat and cover pan to allow the sauce to thicken and pasta to cook. Simmer covered for 13-15 minutes or until the pasta is cooked through.
Finally stir in the half and half and cheddar cheese. Continue stirring until cheese has melted, about 1-2 minutes.
Lastly remove from heat and garnish with parsley.