Eggplant Biryani

Name: Eggplant Biryani
Ingredients: ¾ cup plain whole-milk yogurt; 2 tsp. ground turmeric; Freshly ground black pepper; 2 tsp. Diamond Crystal or 1 tsp. Morton kosher salt, divided, plus more; 4 medium Chinese or Japanese eggplants, halved lengthwise, sliced crosswise on a diagonal 2 thick, or 1–2 medium globe eggplants, cut into 1½ pieces (about 2 lb. total); 1½ tsp. coriander seeds; 2 blades of mace or ¼ tsp. ground mace (optional); 2 tsp. cumin seeds, divided; 2 tsp. Kashmiri chile powder; ½ tsp. ground cinnamon; ¼ tsp. freshly ground nutmeg; 1 cup canola or vegetable oil; 3 large white or yellow onions, 2 thinly sliced, 1 finely chopped; ½ tsp. fennel seeds; 1 1 piece ginger, peeled, finely chopped; 4 garlic cloves, finely chopped; 2 Tbsp. double-concentrated tomato paste; 1 14-oz. can crushed tomatoes; 2 cups basmati rice; 4 green cardamom pods, lightly crushed; 6 whole cloves; 2 bay leaves; 2 Tbsp. Diamond Crystal or 1 Tbsp. Morton kosher salt; Large pinch of saffron threads (optional); 1 serrano chile, halved, thinly sliced, divided; ¾ cup chopped cilantro leaves with tender stems, divided, plus more for serving; Plain whole-milk yogurt and lemon wedges (for serving); A spice mill or mortar and pestle