Fill a large pot with salted water and bring it to a boil. Cook jumbo shells according to package directions until al dente. Drain and set aside.

Heat a large skillet over medium. Add the ground beef and break it up with a spoon. Cook until no pink remains.

Drain excess fat from the pan, leaving a thin film to carry flavor.

Add the canned diced tomatoes with their juices to the beef. Stir in garlic powder, onion powder, and a pinch of salt and pepper. Let the mixture simmer for 3 to 5 minutes.

Reduce heat to low and stir in the cream or milk. Add the shredded cheddar a handful at a time, stirring until the cheese melts and the sauce becomes smooth. Taste and adjust seasoning.

Add the cooked shells to the skillet. Toss gently so each shell is coated in the creamy tomato-beef sauce. Heat through for a minute or two.

Transfer to plates or serve straight from the skillet. Sprinkle chopped fresh parsley over the top if you like and serve hot.