Homemade chocolate turns crumbly I have been making Peanut Clusters a lot lately, and it seems that I just can't get them right. Once I add the butter, the chocolate turns brittle and crumbly before I can shape them on the wax paper. Does anyone know why this is happening and how I can make the chocolate stay smooth until I put them in the fridge?

This is my recipe:  


  1/2 c. sugar
  1/4 c. milk
  1 heaping tbsp. cocoa
  1 heaping tbsp. butter
  1/2 c. roasted peanuts  
  
  Mix sugar, cocoa, and milk. Boil 6 minutes, counting from time the bubbling begins. Add butter, nuts and vanilla. Take from the heat and stir just enough to mix in the nuts. Drop by spoonfuls on waxed paper.`
GdD gives a good answer, but I am going to give a recommendation type answer based on your ingredients because although the quantities are different the ingredients are exactly the same. Go to Hershey.com and search for their fudge recipe. Follow this recipe.

When your "fudge" reaches nearly the desired consistency from stirring, start stirring in the peanuts, and quickly spoon out your clusters onto wax paper.

I think that will give you the desired results and give you a silky fudge chocolate peanut cluster.