Cut the top off the bell peppers. Remove the seeds and pith.
In large pot on medium-high heat, place the ground beef.
Stir and mash to ground beef to make sure it is cooking evenly and to break up any large chunks.
Continue to stir and breakup the ground beef occasionally, until the meat is cooked and there is no pink left.
Add the tomato sauce to the meat and stir to fully incorporate.
Simmer the meat mixture while you get the rest of the ingredients ready.
In a small bowl, mix the ricotta cheese with the parsley and garlic salt.
Grate the cheese.
Preheat oven to 375 ºF (190 ºC).
Place the peppers in an oven proof casserole dish. (If you are stuffing the whole peppers make sure they are tight enough together that they will not fall over.)
Fill half of each pepper with the meat mixture.
Layer in 2-3 spoonful's of the ricotta mixture.
Fill the rest of the pepper up with ground meat mixture.
Place on top a generous heap of grated cheese.
Do this for all of the peppers.
Bake for 35-40 minutes or until the pepper is soft and the cheese is nicely golden.
Remove and allow to cool 5 minutes before serving.