Preheat oven to 350°F/175°C.
Rinse off the peppers. Carefully remove core, seeds and ribs as much as you can using a paring knife. Place the peppers cut-side up in a baking dish that is large enough to hold them upright.
In a large skillet, heat the butter (or olive oil) over medium-high heat. Add the onions, garlic and sauté until lightly golden and fragrant, stirring occasionally. Add the ground beef, season with salt, pepper, soy sauce and honey and cook until no longer pink. During the cooking process, break up the meat with a wooden spatula as needed. Drain any fat.
Once the beef is done, remove from heat. Set aside.
Make mozzarella cream cheese mixture: In a medium bowl, whisk together cream cheese, granulated sugar and salt until combined. Add in shredded mozzarella cheese and herbs (parsley, oregano or Italian seasoning) until combined.
Divide the beef among the bell peppers. Spoon the tomato sauce over the ground beef, divide it evenly for 4 halves of pepper. Let the tomato sauce soak in the ground beef for 2-3 minutes, then evenly add the mozzarella cream cheese mixture on top using a spoon. Sprinkle more mozzarella cheese if desired.
Cover with foil and bake for 15-20 minutes then remove the foil and bake for another 10 minutes, until the mozzarella is melted and beginning to brown.
Allow the peppers to cool for 5 minutes, garnish with parsley or oregano, if using, and serve hot.
Store leftover stuffed peppers in an airtight storage container in the refrigerator for up to about 5 days. Reheat before serving.