Why sugar butter cocopowder mixture got hard in double boiler i was making a fudge brownie without chocolate. The recipe asked to put 1 1/2 cup sugar,3/4+2 tbsp cocopowder and 10tbsps of butter into double boiler and get everthing to be shiny. But when i did the same my mixture ended up as hard sugar rocks and separated butter. Still i managed to stop the disaster by adding little by little water on my own and succeeded. But my fudge brownie ended up to smell like coconut oil. It's not the first time. Once i was making a chocolate frosting and had to do the same,adding sugar butter and coco powder in double boiler until all sugar is melted. But the sugar was not melting as shown in the recipe and it was hard like rock. Please help me a way out.
When I hear the method, I don't see a way it could work as described. 

Suger will neither dissolve in the melted butter, nor will it melt at low temperatures - and the water bath keeps them from getting high enough. I don't see what the double boiler is supposed to do, maybe prevent the butter from browning. But when using this procedure, there is no reason for the sugar to do anything but stay hard. Even if you were to use powdered sugar, it will give a grainy texture to the mixture. 

I was going to tell you to just ditch the recipe for being impossible to work, but on a second thought, I started wondering why you want the sugar to melt in the first place. Upon looking around for brownie recipes with cocoa powder, they do start with melted butter, sometimes even mentioning a double boiler, but none of them had directions to wait until the sugar is melted. Others just skipped the double boiler step and directed to mix the sugar and cocoa powder with the already-melted butter. So your recipe is only bad in the sense of telling you for waiting for the sugar to melt. If you prefer to keep using it, simply wait until the butter in the mixture is melted (with a double boiler or without, as you wish - just don't brown the butter) and keep going with the sugar as hard as-is.