How to Make It
Preheat the oven to 400°. In a large skillet, heat the 1/3 cup of olive oil. Add the tofu, finely chopped onion and garlic and cook over moderately high heat, stirring occasionally, until lightly browned, about 8 minutes. Scrape into a medium bowl and stir in the parsley, mint, scallions, miso and capers. Season with salt.
Trim as little as possible from the bottom of the vegetables so they sit flat. Cut off the top 1/4 inch of the small onions and tomatoes. Lay the zucchini flat and trim 1/4 inch lengthwise off the top. Set the vegetable tops aside. Using a small spoon, scoop out the insides of the vegetables, leaving 1/4-inch-thick walls.
Brush a large rimmed baking sheet with olive oil and arrange the vegetables on the baking sheet. Spoon the filling into the vegetables and cover with the tops. Bake until the vegetables are tender and the filling is hot, 20 to 22 minutes for the tomatoes and 25 to 30 minutes for the onions and zucchini. Transfer to a platter and serve.