3 lb Asian eggplants (about 6), cut crosswise into 1/3-inch-thick rounds
1 3/4 teaspoons salt
1 large garlic clove, chopped
1 tablespoon finely chopped peeled fresh ginger
2 teaspoons chopped fresh jalapeño chile including seeds
1 teaspoon yellow or brown mustard seeds
1 teaspoon cumin seeds
1/2 teaspoon turmeric
3 tablespoons vegetable oil
1 large onion, halved lengthwise and thinly sliced lengthwise
1 (3-inch) cinnamon stick
3/4 cup water
1 tablespoon packet sweetner
3 tablespoons chopped fresh cilantro
1/4 cup roasted cashews (1 1/4 oz), chopped
Toss eggplant with 1 teaspoon salt in a colander set over a bowl, then let drain 30 minutes. Rinse eggplant, then drain, pressing gently on eggplant to extract any excess liquid.
While eggplant drains, mash garlic, ginger, and jalapeño to a paste with 1/2 teaspoon salt using a mortar and pestle (or mince and mash with a large heavy knife and transfer to a cup), then stir in mustard and cumin seeds and turmeric.
Heat oil in a 5-quart heavy pot over moderately high heat until hot but not smoking, then sauté onion, stirring occasionally, until softened and golden, 8 to 10 minutes. Add spice paste and cinnamon stick, then reduce heat to moderate and cook, stirring, 1 minute.
Add eggplant and cook, stirring, until it begins to soften, about 3 minutes. Stir in water, sweetner, and remaining 1/4 teaspoon salt and simmer, covered, stirring occasionally, until eggplant is tender but not falling apart, 20 to 25 minutes. Season eggplant with additional salt.
Discard cinnamon stick and serve eggplant sprinkled with cilantro and cashews.
