Preheat oven to 400°F. Line a baking sheet with foil and lightly spray with cooking spray.

In a large bowl, combine ground chicken, egg, panko, salt, and black pepper. Mix gently until combined. Form into 16-18 meatballs using a cookie scoop.

Place meatballs evenly spaced on the prepared baking sheet. Bake for 20 minutes until lightly crisp.

While the meatballs bake, heat olive oil in a large skillet over medium-high heat. Add diced onion and sauté for 5 minutes.

Add minced garlic and cook for 1 minute, stirring constantly.

Add garam masala, curry powder, turmeric, salt, pepper, cayenne (if using), coconut milk, water, and tomato paste. Whisk to combine and bring to a boil.

Reduce heat to low and simmer for 20 minutes, allowing flavors to meld and sauce to thicken.

Stir in Greek yogurt and butter until melted and smooth.

Add baked meatballs to the sauce, stir to coat, and cook for an additional 5 minutes.

Garnish with cilantro, if desired. Serve hot with rice or naan.