Heat the oil in a large saucepan or large, wide frypan with a cover, over medium-high heat. Add the shallots and easy chillies and cook for one minute. Add the coriander, cumin, fenugreek, cinnamon, cayenne, clove, and cardamom and stir to mix well. Cook, stirring constantly, until the mixture turns a couple shades darker and becomes very fragrant.
Add the garlic and ginger, mix, and cook one more minute. Add the chicken, stir to coat in the spices, and stir fry for three to four minutes. Add the lemongrass, salt, paprika, and water, stir, and bring to a simmer. Reduce the heat to low and simmer, covered, for 30 minutes. Add the coconut milk and simmer, uncovered, on low heat until the sauce is hot and the chicken is cooked through and sauce begins to thicken.
Top with coriander leaves, if desired.