In a large bowl, combine the ground chicken, lemongrass, egg, breadcrumbs, garlic, ginger, fish sauce, curry paste, and cilantro. Season with salt and pepper.
Gently mix until just combined—do not overwork the mixture.
Form into about 12 evenly sized meatballs. Place on a lined baking sheet and set aside in the fridge.
Heat a large skillet over medium heat with a drizzle of oil. Cook the meatballs, turning occasionally, until browned on all sides and cooked through, about 8–10 minutes. Remove and set aside.
In the same skillet, heat the olive oil. Add the diced onion and cook until soft and translucent, about 3–4 minutes.
Stir in the garlic and ginger and cook until fragrant, about 1 minute. Add the bell pepper and green onions, and simmer for 5–7 minutes. Add the curry paste and season.
Add the coconut milk, coconut cream, chicken stock, fish sauce, and brown sugar. Stir well and bring to a gentle simmer.
Return the meatballs to the skillet and simmer for another 5-8 minutes, spooning the sauce over them.
Finish with lime zest, lime juice, and fresh cilantro.
Serve the meatballs and curry sauce over jasmine rice. Garnish with lime wedges, cilantro, and chopped Thai chilies for heat.