Line a 9 tray with aluminium foil and grease the foil.
Put the coconut, sugar, salt and evaporated milk in a large microwave safe bowl and mixrowave on high, for 15 minutes, stirring after every 5 minutes. Cook until mixture thickens. Cooking time is only an estimate as wattage of microwave differs.
Add in butter and continue to cook 1 or 2 minutes at a time and stir.
When the mixture is really thick, quickly add in rose essence and coloring.
The candy is ready when the mixture leaves the sides of the bowl, almost like a lump. Also, the mixture will lose some of its shine, almost going matte. To test for doneness, roll a small piece into a ball and put ball into a glass of water, if the ball does not disintegrate, it is done.
Working quickly, pour out the hot mixture into the greased tin and flatten top with the back of a clean rubber spatula.
Let cool ten minutes and cut into squares whilst warm with a pizza cutter. Let cool completely. Lift the aluminium foil from the tray and using a sharp knife, complete the cutting the edges, where the pizza cutter could not reach. Break off the cut squares and serve or store in an air-tight container.