Easy Butter Chicken with a Twist

Name: Easy Butter Chicken with a Twist
Cuisine: Asian, Indian
Ingredients: 2 lbs. chicken breast cut into 1-inch cubes; 1 tsp chili powder; 1 tsp salt; ½ tsp pepper; 1/2 tsp ground turmeric; 6 Tbsp butter (divided); 1 cup onion (diced); 1 red pepper (chopped (optional)); 1 Tbsp grated ginger; 3 garlic cloves (minced); 3 tsp of garam masala; 1 tsp cumin; 1 tsp cayenne pepper (optional if you don't like heat); ½ tsp cinnamon; pinch of salt and pepper; 14 oz can tomato sauce; 1 cup water; 3/4 cup 10% cream; ½ cup dated (pitted, chopped (optional)); ½ cup pistachio nuts (chopped (optional)); chopped cilantro or parsley