Step 1

Whisk together yogurt, turmeric, a few grinds of pepper, and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt in a large bowl. Add eggplant and toss with your hands until well coated. Let sit at room temperature 30 minutes.

Step 2

Meanwhile, grind coriander seeds, mace blades (if using), and 1½ tsp. cumin seeds in spice mill or with mortar and pestle to a fine powder. Transfer to a small bowl and mix in chile powder, cinnamon, and nutmeg (if you’re using ground mace, add it here).

Step 3

Heat oil in a large (6–7-qt.) Dutch oven or other heavy pot over medium-high. Stir in half of sliced onions and cook, stirring occasionally, until deep golden brown, 9–12 minutes. (Keep an eye on the onions during the last few minutes, as they will darken quickly.) Using a slotted spoon, transfer onions to a paper-towel-lined plate to drain. Repeat process with remaining sliced onions; set onions aside.

Step 4

Reduce heat to medium and add fennel seeds and remaining ½ tsp. cumin seeds to pot. Cook until seeds start to sputter and turn a shade darker, 30–60 seconds. Add chopped onion and ginger and cook, stirring occasionally, until onion is translucent and starting to turn golden, 7–9 minutes. Add garlic and tomato paste and cook, stirring, until tomato paste is brick red and garlic is fragrant, about 2 minutes. Add spice mixture; cook, stirring constantly, until very fragrant, about 1 minute.

Step 5

Add eggplant along with any marinade to pot. Cook, stirring constantly, 3 minutes. Using a wooden spoon, stir in crushed tomatoes, remaining 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, and ½ cup water, scraping up any browned bits stuck to the bottom of pot. Reduce heat to low, cover pot, and cook, stirring occasionally, until eggplant is cooked through and easily pierced with a fork, 30–45 minutes.

Step 6

Uncover pot, increase heat to medium-low, and cook until sauce is reduced by a third and clings to eggplant (you don’t want the masala to be too wet or it will result in soggy rice), 8–10 minutes. Taste and season with more salt if needed. Remove from heat and cover pot to keep eggplant masala warm.

Step 7

While the eggplant is cooking, place rice in a medium bowl and rinse in several changes of cold water, swishing rice with your fingers, until water runs almost clear. Fill bowl with cold water to cover rice by 2" and let soak at room temperature 30 minutes; drain.

Step 8

Bring a large pot of water to a boil. Add cardamom, cloves, bay leaves, and salt; boil 2 minutes to infuse. Stir in rice and cook until barely al dente, about 4 minutes. Drain and set aside. Pick out and discard the whole spices if desired.

Step 9

Place a rack in middle of oven; preheat to 400°. Place saffron (if using) in a small bowl and cover with 2 Tbsp. hot water. Let sit at least 15 minutes.

Step 10

Transfer half of eggplant masala to a medium bowl and set aside. Spread remaining eggplant masala in an even layer in its pot. Top with half of rice (do not pack it down; you want to give the rice space to cook fully and become fluffy). Top with half of chile, half of cilantro, and half of reserved fried onions. Layer with reserved eggplant masala, then with remaining rice. Drizzle with saffron water (including saffron threads); scatter remaining chile, cilantro, and fried onions over top.

Step 11

Cover pot with a tight-fitting lid and bake 25 minutes. Let biryani sit, still covered (do not peek!), 15 minutes.

Step 12

Mound biryani on a platter or serve straight from pot. Top with lots of chopped cilantro; serve with yogurt and lemon wedges.