I found the recipe below on Allrecipes.com and I decided to give it a try as the precooking of the meat significantly shortens the baking time, which should result in higher moisture content and tenderness. It sure did! When I tested the recipe I made a number of changes/improvements and those changes are reflected in the recipe below.
All the folks who have tried this dish love it. Now I get to a real departure from typical stuffed green pepper recipes. The big change is to avoid overbaking the green peppers so they still have some substance and better color. This is accomplished by reducing the typical baking time and starting with raw peppers, which works because the other ingredients, except for the cheese and the second can of tomato sauce, are precooked. The peppers in the real dish looked much better than the ones in the picture shown with this recipe. Well, enjoy ... I certainly do.
Bring the water to a boil in a medium saucepan. Add the rice and stir. Reduce heat to very low, cover the saucepan with a lid and simmer the rice for 22 minutes. Remove the saucepan from the heat and leave it covered.
Preheat the oven to 350º F.
Place the halved and cleaned green bell peppers in a 9"x13" baking dish.
Brown the ground beef and the sausage in a large skillet over medium heat and then drain it. Return the meat mixture to the skillet and mix in the diced onion, cooked rice, diced garlic, salt and pepper. Pour in one can of the tomato sauce and mix thoroughly. Let the mixture simmer on very low heat for about 10 minutes, covered. Remove the skillet from the heat.
Spoon the skillet mixture, heaping, into/onto each half of the green peppers. Pour the second can of tomato sauce evenly over the mixture/peppers.
Bake the stuffed peppers in the preheated oven for 50 minutes.
Sprinkle the mozzarella cheese over the top of each stuffed pepper. Return the peppers to the oven and bake them for 10 minutes.
Serve hot. Expect applause.