Slightly adapted from The Indian Slow Cooker, this recipe serves 8 (can be halved).
2 medium eggplants, stem end removed, cut into 1/2-inch dice (approx. 10-12 cups)
1 large Idaho or Yukon Gold potato, peeled, cut into 1/2-inch dice
1 medium yellow or red onion, peeled and chopped
1 tsp ginger paste (or grated fresh ginger root)
6 cloves garlic, peeled and coarsely chopped
2 jalapeño chiles, seeded and minced
1 Tbsp ground cumin
1 Tbsp ground red chile pepper
1 Tbsp garam masala
1 tsp turmeric
1/4 cup canola oil
1 Tbsp kosher salt, or to taste
1-2 Tbsp chopped fresh cilantro, to taste
Combine eggplant, potato, onion, ginger, garlic, jalapeño peppers, cumin, ground chile pepper, garam masala, turmeric and oil in a 4- or 5-quart slow cooker. Stir as best you can to distribute the spices and oil. (The smaller cooker will be frighteningly full, but don't worry; the eggplant will cook down.) Cook on HIGH for 2 hours, stirring after 1 hour.
After the first two hours of cooking, stir well. There should be a nice amount of moisture in the cooker, and the eggplant should have collapsed a bit. If there is plenty of liquid in the pot, continue cooking on LOW for 30 minutes, uncovered. If there's not much liquid, cook on LOW for 30 minutes with the cover on.
Add the salt and cilantro, to taste. (Salt added during the cooking will draw more moisture out of the eggplant, so it's best added at the end.)
Serve at room temperature, over rice or topped with raita, or make ahead.