Moqueca is a typical Brazilian seafood stew, and moqueca de camarão uses prawns and coconut milk. It's quick to make and uses simple ingredients. Perfect with rice.
Also called achiote powder, it can be found at Asian or Latin American shops, or online. Annatto is mostly used for the vibrant colour it imparts, so in a pinch you could either omit it from the recipe or use equal parts paprika and turmeric instead.