1. Preheat the oven to 400°F. Cut 1/2 inch from the top (stem end) of each bell pepper and tomato. Finely chop the tomato tops to measure 1 cup and reserve, discarding the tomato stems, if necessary. Discard the bell pepper tops. Scoop out and discard the pulp and seeds from the bell peppers and tomatoes.

2. Place the bell pepper shells, cut sides up, in a lightly greased 8-inch square baking dish. Drizzle with 1 tablespoon of the oil. Bake until the peppers begin to soften, about 10 minutes. Remove from the oven, and set aside. Increase the oven temperature to broil with the oven rack 5 inches from the heat.

3. Heat the remaining 1 tablespoon oil in a large skillet over medium.

4. Add the onion, fennel bulb, oregano, cumin, 1/2 teaspoon of the salt, and 1/4 teaspoon of the black pepper; cook, stirring occasionally, until the onion is translucent, about 8 minutes. Add the garlic, and cook, stirring often, until fragrant, about 1 minute. Add the water and reserved 1 cup chopped tomatoes to the skillet; cook, stirring often, 3 minutes. Remove from the heat; stir in the quinoa, olives, feta, fennel fronds, 2 tablespoons of the parsley, and 1/4 teaspoon of the salt.

5. Stir together the panko, Parmesan, and remaining 2 tablespoons parsley in a small bowl. Add the melted butter, and stir to combine.

6. Add the tomato shells to the baking dish, alternating with the bell pepper shells. Sprinkle the cavities evenly with the remaining 1/4 teaspoon salt and 1/4 teaspoon black pepper. Divide the quinoa mixture evenly among the tomato and bell pepper shells. Top evenly with the panko mixture.

7. Broil until the panko mixture is golden brown, about 2 minutes.