Combine all the ingredients for the sauce in a high-speed blender, and blend on high until smooth. If you don’t have a high-speed blender, first grind the whole spices in a spice grinder or mortar and pestle, then add everything to a blender or food processor and process until smooth. Set aside until needed.
Heat the oil in a wide, deep saucepan over medium-high heat. When hot, add the onion and a pinch of salt, and cook until softened and translucent, approximately 7 to 10 minutes. Add the eggplant, mushrooms, and cauliflower, and cook for an additional 2 to 3 minutes, until just heated. Pour the blended sauce over the vegetables, mixing well, and bring to a boil. Cover, reduce the heat to medium-low, and allow to cook for 15 minutes.
Stir in the chickpeas, frozen peas, vinegar, and sugar, then allow to cook for 15 to 20 minutes more, until the vegetables are very tender. Taste, adjust seasonings as necessary, and garnish with cilantro just before serving. Leftovers will keep in the refrigerator for 3 to 5 days.