Homestyle Stuffed Peppers

Step 1
Bring a large pot of water to a boil. Add peppers and boil until softened, 4 to 5 minutes. Transfer peppers to a colander and run under cold water to cool.

Step 2
Preheat the oven to 350 degrees F (175 degrees C). Stir tomato sauce and vinegar together in a bowl.

Step 3
Mix ground beef, cooked rice, bread crumbs, 4 tablespoons Parmesan, onion, egg, garlic powder, salt, and pepper together in a large bowl until well combined. Spoon beef mixture into peppers. Place peppers into a 9×13-inch baking dish with the stuffing facing up. Pour tomato sauce mixture over peppers, then sprinkle remaining 2 tablespoons Parmesan over top.

Step 4
Bake in the preheated oven, basting peppers with sauce several times, until beef filling is no longer pink in the center, about 1 hour 20 minutes. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).