In a small pot, bring beef stock to a boil. Turn stove burner off, add instant rice to beef stock, cover and set aside.
Cut off the top of each pepper, pull out any remaining stem and scrape out the seeds and membranes. Set aside.
In a large bowl, combine ground beef, rice, diced tomatoes, onion, garlic, Italian seasoning, salt, pepper, 1 cup of Shredded Sharp Cheddar cheese and grated Parmesan cheese.
Stuff each pepper with ground beef mixture.
Pour 1/4 cup of water into bottom of slow cooker and place peppers on top.
Cook peppers on low for 6 hours, or high for 4 hours, until peppers are tender and ground beef is cooked through.
About 15 minutes before peppers are done, sprinkle remaining shredded cheese on top to melt.
