Slow-Cooker Butter Chicken

Name: Slow-Cooker Butter Chicken
Prep time: 30 min
Cook time: 3 h
Total time: 3 h 30 min
Cuisine: Indian, Asian
Ingredients: 2 tablespoons butter; 1 medium onion, chopped; 4 garlic cloves, peeled, thinly sliced; 2 teaspoons garam masala; 2 teaspoons red curry powder; 1/2 teaspoon chili powder; 1 teaspoon ground ginger; 2 tablespoons whole wheat flour; 1 tablespoon olive oil; 1 can (14 ounces) coconut milk; 1/4 cup tomato paste; 1 teaspoon salt; 1/4 teaspoon pepper; 3 pounds boneless skinless chicken breasts, cut into 1-inch pieces; Hot cooked rice; Optional: Fresh cilantro leaves and naan bread