Use Cannelloni or Manicotti Pasta. Either of these large, tubed pasta types work well. No need to pre-boil the pasta!
Cook the filling in a skillet and then chop it in a food processor or a Ninja type blender. It should be minced, but not as smooth as a paste.
In a 13×9 casserole pan, add just enough marinara sauce to coat the bottom of the pan. This keeps the tubes from sticking.
Stand the tubes up and stuff the beef mixture using a piping bag, large funnel, or ziplock bag. Lay stuffed pasta into the casserole dish.
Pour remaining sauce over tubes. Sprinkle mozzarella, parmesan, and parsley over the casserole. Cover with foil.
Bake for 35 minutes or until cheese is thoroughly melted and the edges are bubbling. Remove foil. Bake another 10 minutes or until the cheese is starting to brown.