Step 1

In a small bowl, combine the rice and lentils and add water to cover. Soak for at least 1 hour and up to overnight, then drain.

Step 2

Cut off the stem ends of the zucchini and summer squash, and cut the stem end off the bell pepper, about an inch from the top; reserve these bits. Halve each squash lengthwise. Using a spoon or corer, remove the flesh in a channel from the zucchini and squash and chop the flesh. Discard the seeds from the bell pepper. Use a fork or skewer to poke holes all over the outside of the vegetables.

Step 3

Set a shallow Dutch oven, or other heavy-duty, lidded pan that can hold the vegetables in one layer, over medium heat. Pour in the olive oil, and when it shimmers, add the onion and cook, stirring, until it softens and lightly browns, about 5 minutes. Add the soaked rice and lentils, the chopped vegetable flesh, 1/2 cup of the water, the parsley, quinoa, 1 tablespoon of the lemon juice, the spice mix and 1/2 teaspoon of the salt. Cook, stirring frequently, until the rice and lentils start to soften slightly, about 10 minutes.

Step 4

Remove from the heat, let the mixture cool slightly, then fill the zucchini and squash halves with it, mounding the filling if necessary to use it all, and place one half on top of the other to close them up as much as possible. (Don’t worry if some of the filling is exposed.) Fill the red bell pepper with the filling, again mounding it if needed to use it all. Place the vegetables in the same pan and nestle the reserved cut stem ends against the squash and zucchini, and place the stem-end top back on the bell pepper, to prevent the filling from spilling out too much during cooking.

Step 5

In a large measuring cup or bowl, mix together the diced tomatoes with the remaining 1 cup of water, the tomato paste, the remaining 2 tablespoons of lemon juice, the remaining 1/2 teaspoon of salt and the pepper. Pour it over the stuffed vegetables in the pan.

Step 6

Set the pan over medium-high heat and bring the mixture to a boil. Reduce the heat to medium-low, cover and cook until the vegetables are tender and the rice and lentils are cooked, 30 to 45 minutes.

Step 7

Garnish with the additional whole parsley leaves and serve hot.