Chicken Vindaloo

Ingredients

• 3 cups chopped onions
• 1 1/2 cups chopped seeded tomatoes (about 4 medium)
• 2 1/2 tablespoons distilled white vinegar
• 1 large garlic clove, chopped
• 1 teaspoon minced peeled fresh ginger
• 1 teaspoon tomato paste
• 1 teaspoon garam masala*
• 1 teaspoon ground turmeric
• 1/2 teaspoon paprika
• 1/2 teaspoon ground cumin
• 1/2 teaspoon ground coriander
• 1/4 teaspoon (or more) cayenne pepper
• 2 tablespoons vegetable oil
• 6 skinless boneless chicken thighs, cut into 1- to 1 1/2-inch pieces
• 1 1/2 pounds russet potatoes, peeled, cut into 1-inch pieces
• 1 1/2 cups low-salt chicken broth or water