Preheat your oven to 350°F. While the oven heats, halve the bell peppers lengthwise and remove all seeds and membranes, creating two boat-shaped halves per pepper. Rinse them briefly and set aside on your baking dish or a 9x13 inch casserole dish. Start cooking the rice according to package directions in a separate pot—this will take about 15-20 minutes and can cook while you prepare the other components. I always use Mahatma long-grain white rice because it holds up well when mixed with other ingredients and doesn't get mushy.

While the rice cooks, dice the onions and mushrooms into roughly 1/2-inch pieces and chop the bell pepper tops (the parts you removed from the halved peppers). Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the chopped onions and cook for 2 minutes until they begin to soften, then add the mushrooms and chopped pepper tops. Sauté for 5-7 minutes, stirring occasionally, until the vegetables are tender and any liquid from the mushrooms has mostly evaporated. This develops deeper flavor and ensures the vegetables won't release excess moisture in the finished dish.

Add the chopped shrimp to the vegetable mixture in the skillet and cook for 2 minutes, stirring gently, just until the shrimp turns pink and opaque—do not overcook or the shrimp will become tough and rubbery. Sprinkle in the garlic powder and paprika, stirring to distribute the seasonings evenly throughout the mixture. Cook for another 30 seconds to bloom the spices.

When the rice is tender and has absorbed all its liquid, add it to the skillet with the shrimp and vegetable mixture. Stir gently to combine everything evenly, making sure the rice coats with the oils and seasonings. I like to give it a taste at this point and adjust seasoning if needed—a pinch of salt can really bring out the shrimp and vegetable flavors.

Spoon the shrimp and rice filling evenly into each pepper half, packing it gently but firmly so the mixture sits slightly mounded in each pepper. Arrange the stuffed peppers in your baking dish and pour about 1/4 cup water around (not over) them—this creates steam and prevents the peppers from drying out. Cover the dish tightly with foil and bake at 350°F for 30 minutes, which allows the peppers to become tender while the filling stays moist.

Carefully remove the foil from the baking dish (watch out for the steam). Sprinkle the cheese blend evenly over the top of each stuffed pepper half, distributing it generously so each pepper gets a good amount. Return the dish to the oven, uncovered, and bake for 5-10 minutes until the cheese is melted and lightly golden. The peppers are now tender and the filling is hot throughout, with a delicious cheesy top.