Heat the oil in a large pot. Sauté onions for a few minutes, then add curry powder, garlic, ginger, and chili pepper. Continue frying over high heat for a few more minutes, stirring continuously. Add Eggplant and potatoes, stir fry until Eggplant begins to brown. Reduce heat. Simmer for 10 minutes. Stir in tomatoes and tomato paste. Adjust seasoning. Simmer until sauce is thickened and everything is tender. Stir in coconut milk. Serve with boiled rice.