Heat the oil in a large, deep skillet over medium heat until shimmering. Add the onion and cook, stirring frequently until soft and golden, about 15 minutes (reduce the heat to medium low, if necessary, to prevent the onion from burning). Stir in the ginger and garlic and cook for 2 minutes. Add the eggplant, yellow squash, zucchini, and 1/2 teaspoon salt; stir to coat thoroughly. Cook over medium heat , stirring occasionally, until the vegetables are barely tender, 7 to 10 minutes.

Stir in the garam masala, coriander, cumin, turmeric, chile, 1 teaspoon salt, and a few grinds of pepper. Cook until the spices are fragrant, 1 to 2 minutes. Pour in the chickpeas and their liquid, the tomato sauce, coconut milk, and 2 tablespoons of the cilantro.

Raise the heat to medium high and bring the stew to a boil. Reduce the heat to medium low and simmer, uncovered, until the eggplant and zucchini are completely tender but still hold their shape, and the sauce has thickened, 15 to 20 minutes.

To serve, ladle the stew into shallow rimmed bowls and sprinkle with the remaining 1/4 cup cilantro and the toasted coconut (if using).

Bring a large pot of water to a rolling boil. Rinse the tomatoes in cold water. With a paring knife, cut an X into the bottom of each tomato. (This will make it easier to peel the tomatoes once they're blanched.) Carefully lower about 10 tomatoes into the boiling water and leave them for 20 to 30 seconds. Use a slotted spoon to move them to a large bowl filled with ice water. Continue blanching the tomatoes in batches and transferring them to the ice water.

Use a paring knife and your fingers to remove the skin from the tomatoes¿it should peel off easily. Cut the tomatoes lengthwise into quarters, core, and remove the seeds. Coarsely chop the tomatoes and transfer them to a bowl.

Heat the oil and the garlic in a 5- to 6-quart heavy-duty pot over medium-low heat until the garlic begins to sizzle and very lightly browns, 3 to 4 minutes. Carefully pour in the tomatoes. Raise the heat to medium high and bring the tomatoes to a boil. Stir in the salt, reduce the heat to medium, and let the sauce simmer, stirring occasionally, until the tomatoes have broken down and the sauce has thickened, about 1 hour. Remove from the heat and discard the garlic.