Chef John's Stuffed Peppers

Step 1
Bring rice and water to a boil in a saucepan over high heat. Reduce heat to medium-low, cover, and simmer until the rice is tender, and the liquid has been absorbed, 20 to 25 minutes. Set the cooked rice aside.

Step 2
Meanwhile, preheat the oven to 375 degrees F (190 degrees C).

Step 3
Make sauce: Cook onion and olive oil over medium heat until onion begins to soften, about 5 minutes. Transfer 1/2 of the cooked onion to a large bowl and set aside.

Step 4
Stir marinara sauce, beef broth, balsamic vinegar, and red pepper flakes into the skillet with cooked onion; cook and stir for 1 minute.

Step 5
Pour sauce mixture into a 9×13-inch baking dish and set aside.

Step 6
Combine ground beef, Italian sausage, diced tomatoes, Italian parsley, garlic, salt, black pepper, and cayenne pepper into the bowl with reserved onions; mix well. Stir in cooked rice and Parmigiano Reggiano. Stuff green bell peppers with beef and sausage mixture.

Step 7
Place stuffed green bell pepper halves in the baking dish over tomato sauce; sprinkle with remaining Parmigiano-Reggiano, cover baking dish with aluminum foil, and bake in the preheated oven for 45 minutes.

Step 8
Remove aluminum foil and bake until the meat is no longer pink, the green peppers are tender and the cheese is browned on top, an additional 20 to 25 minutes.