Vegetarian Biryani

Name: Vegetarian Biryani
Ingredients: 4 tablespoons olive oil; 1 cup yogurt; 3 tablespoons raisins; 3 tablespoons cashew nuts; 2 red chilies; 4 tablespoons couscous (soaked in water overnight); 1 teaspoon coriander powder; 1 teaspoon cumin seed; 1⁄2 teaspoon garam masala (better if you can get Birayani masala or spice); 3 large onions, sliced; 1 teaspoon garlic paste (grated); 1 teaspoon ginger paste (grated); 1⁄2 teaspoon whole cloves; 1 teaspoon black peppercorns; 1 teaspoon cardamom; 2 black cardamom pods; 2 pieces cinnamon sticks; 2 cups mangoes (cubed pieces); 12 pieces potatoes, 1-inch pieces deep fried (optional); 2 cups rice; 6 medium tomatoes; lemon juice; 2 teaspoons salt; 1⁄4 cup saffron milk (roast saffron and add to to lukewarm milk and stand for 5 hrs)