Ingredient:

• 2 tablespoons vegetable oil
• 1 onion, sliced
• 1 teaspoon garlic paste
• ½ teaspoon ginger paste
• 1 tablespoon ground coriander
• 1 teaspoon ground cumin
• ½ teaspoon ground turmeric
• ½ teaspoon chile powder
• ¼ teaspoon ground black pepper
• ¼ cup tomato puree
• 1 ¼ cups water
• 1 tablespoon vinegar
• salt to taste
• 4 hard-boiled eggs, halved