Preheat the oven to 450°F (230°C) and line a baking sheet with parchment paper.
In a mixing bowl combine the ground turkey or chicken, egg, panko, and a pinch of kosher salt and black pepper; mix until just combined.
Coat your hands with a little olive oil and roll the mixture into tablespoon-sized meatballs (about 15–20); place them on the prepared baking sheet.
Bake the meatballs for 15 minutes, until cooked through and slightly crisp on the outside.
While the meatballs bake, heat 1 tablespoon olive oil in a large skillet over medium heat. Add the chopped onion and cook about 5 minutes until softened and fragrant.
Add the garlic and grated ginger and cook another 1–2 minutes until aromatic; season with salt and pepper.
Stir in the garam masala, curry powder, turmeric, and cayenne and cook for about 1 minute until fragrant.
Add the tomato paste, coconut milk, and 1/2 cup water; stir to combine, bring to a gentle boil, and simmer about 5 minutes until the sauce thickens slightly.
Off the heat, stir in the Greek yogurt and butter until smooth, then add the baked meatballs to the skillet and return to low heat; cook, stirring occasionally, about 3–5 minutes to warm through and thicken the sauce slightly.
Remove from heat and stir in the chopped cilantro.
Serve the meatballs and sauce over steamed rice with naan on the side.
