1Heat the oven to 375°F. Bring 1 1/2 cups of water and a pinch of salt to a boil in a saucepan, stir in the rice, cover, and simmer on low for about 15 minutes, until the water is absorbed. Fluff and set aside.
2Trim a thin slice off the bottom of any pepper that wobbles so it stands upright. Stand the peppers snugly in a baking dish.
3Warm the olive oil in a large skillet over medium-high heat. Crumble in the beef and brown it, breaking it up, for 6 to 8 minutes. Spoon off excess fat if the pan looks greasy.
4Add the onion to the beef and cook 4 minutes until soft. Stir in the garlic, tomato paste, paprika and oregano and cook 1 minute until the paste darkens slightly.
5Pour in half of the crushed tomatoes along with the Worcestershire. Simmer 3 minutes, then fold in the cooked rice and season well with salt and pepper. Taste it; the filling should be boldly seasoned since the peppers are mild.
6Spoon the filling into the peppers, packing it in and mounding it a little on top. Spread the remaining crushed tomatoes around the bases of the peppers and season the sauce with a pinch of salt.
7Cover the dish tightly with foil and bake 35 minutes. Uncover, sprinkle the cheddar over the tops, and bake 10 to 15 minutes more until the peppers are tender when pierced and the cheese is bubbly and spotted gold.
8Rest 5 minutes. Spoon pan sauce over each pepper and finish with parsley.