Crock Pot Butter Chicken: Easiest Indian Feast!

Ingredients

• 2 lbs (900g) boneless, skinless chicken thighs, cut into 1-inch cubes
• 1 tbsp (15ml) olive oil
• 1 medium yellow onion, finely chopped
• 2 cloves garlic, minced
• 1 inch (2.5cm) ginger, grated
• 1 tsp garam masala
• 1 tsp ground cumin
• 1/2 tsp turmeric powder
• 1/4 tsp cayenne pepper (optional, for heat)
• 1/2 tsp salt, or to taste
• 1/4 tsp black pepper, or to taste
• 1 (28 oz / 800g) can crushed tomatoes
• 1 cup (240ml) heavy cream
• 1/4 cup (60g) unsalted butter, cut into pieces
• 2 tbsp (30ml) tomato paste
• 1 tbsp brown sugar (packed)
• 1/4 cup (60ml) chopped fresh cilantro, for garnish (optional)