These Serbian-style stuffed red bell peppers are filled with a savory mixture of mushrooms, rice, and onions, then gently simmered in tomato sauce until tender. Inspired by traditional Orthodox Lenten cooking, this simple, comforting dish is completely plant-based and makes a satisfying lunch or dinner.
Prepare the peppers: Cut off the tops of the red bell peppers and remove the seeds and membranes, keeping the tops to use as lids. Finely chop the onion and mushrooms, and rinse the uncooked rice.
Make the filling: Heat the olive oil in a large skillet over medium heat. Add the onion and cook for about 8 minutes, until softened. Add the mushrooms and continue cooking, stirring occasionally, until they release their moisture and most of the liquid has evaporated. Stir in the uncooked rice, half the salt, and the black pepper.
Stuff the peppers: Spoon the mushroom and rice mixture into the peppers, filling each about three-quarters full to leave room for the rice to expand (this is very important!). Replace the pepper tops loosely and arrange the peppers upright in a deep, heavy-bottomed pot, packing them snugly enough to prevent them from tipping over.
Add the tomato sauce: Mix the tomato passata with the water and remaining salt. Pour the mixture around the stuffed peppers. The liquid should come partway up their sides.
Simmer: Bring the liquid to a gentle simmer, then reduce the heat, cover, and cook for approximately 50–60 minutes. Check occasionally and add a little hot water if the sauce reduces too much
Check and serve: Test the rice inside one pepper to make sure it's completely tender. Continue cooking for a few more minutes if necessary. Remove the pot from the heat and let the peppers rest for 10 minutes before serving, allowing two peppers per person with some of the tomato sauce.