Vegetarian Biryani

Name: Vegetarian Biryani
Ingredients: 1 1/2 cups rice, preferably basmati, rinsed; 1 tablespoon butter; 1 tablespoon cooking oil; 1 onion, chopped; 2 cloves garlic, minced; 1 tablespoon grated fresh ginger; 1/2 teaspoon ground cumin; 1 teaspoon turmeric; 1/2 teaspoon curry powder; 1/8 teaspoon cayenne; 1 baking potato (about 1/2 pound), peeled and cut into 1 1/2-inch pieces; 2 carrots, cut into 1 1/2-inch pieces; 2 cups water; 1 1/2 teaspoons salt; 1 10-ounce package frozen peas, defrosted; 1/4 cup plain yogurt; 1 jalapeño pepper, seeds and ribs removed, minced; 1 tomato, seeded and cut into 1/2-inch pieces; 1/2 cup cilantro leaves