Heat clarified butter in a large frying pan over medium heat. Add the thyme and cook for 3 minutes, until fragrant. Remove from heat and stir in orange zest. Pour butter into small bowl.
Return the pan to the heat, add garlic and cook for 1 minute. Add the prawns and chilli powder; shake or toss in the pan for 3-5 minutes, until the prawns are no longer transparent. Return the butter to the pan and serve with crusty baguette.