Char the lemongrass, halved ginger, and onion in a large dry skillet over high heat—really blacken these seasonings on both sides. Transfer them to a pot or casserole.
Combine the cinnamon, star anise, and chiles in a small skillet and turn the heat to medium. Toast, shaking the skillet periodically, until the spices are fragrant, just a minute or two. Add them