Chicken in a Cashew Nut Sauce

INGREDIENTS

• 2 medium onions
• 2 tablespoons tomato paste
• 1/3 cup cashew nuts
• 1 1/2 teaspoons garam masala
• 1 teaspoon garlic, pulp
• 1 teaspoon chili powder
• 2 tablespoons lemon juice
• 1/4 teaspoon ground turmeric
• 1 teaspoon salt
• 1 tablespoon low-fat plain yogurt
• 2 tablespoons oil
• 2 tablespoons fresh coriander
• 1 tablespoon sultana
• 1 lb boneless skinless chicken, cubed
• 2 1/2 cups button mushrooms
• 1 1/4 cups water