How to Make It
In a large skillet, heat the oil. Add the onion and cook over moderate heat, stirring occasionally, until softened, 5 minutes. Add the eggplant, garlic, oregano, cumin, paprika and crushed red pepper and season with salt. Cook, stirring, until fragrant, 1 minute. Add the lamb and cook, breaking up the meat into small pieces with a wooden spoon. Add the tomato paste and cook, stirring, for 2 minutes. Stir in the stock and bring to a boil. Cover and cook over low heat until the sauce is thickened, 12 minutes.
Cook the pasta in a pot of salted boiling water until al dente, 8 minutes. Drain, reserving 1/2 cup of the pasta cooking water. Stir the pasta and 1/4 cup of the reserved cooking water into the sauce; add more water if a thinner sauce is desired. Remove the skillet from the heat and stir in the yogurt and mint. Season with salt and serve hot.