Slice the top and bottom off the peppers, then cut each pepper into three thick rings
Mix all other ingredients (except Parmesan cheese) in a large bowl, using your hands to mix it well
Stuff ~3/4 cup of the meat mixture into each pepper ring
Brown each pepper ring in a large frying pan over medium-high heat, about 3-4 minutes per side
Place the browned pepper rings into a baking dish
Top with crushed tomatoes (optional)
Bake at 350 for 35-40 minutes
Pull out of the oven and top with Parmesan cheese (optional)