Old Fashioned Cooked Chocolate Frosting
["2 1/4 c. sugar", "8 Tbsp. cocoa", "1 egg", "1/4 tsp. salt", "10 Tbsp. milk", "1 tsp. vanilla", "1 lump butter (about 1/2 stick)"]
["Cook!", "Bring mixture to full boil and allow to cook for a few minutes, stirring constantly."]
["sugar", "cocoa", "egg", "salt", "milk", "vanilla", "lump butter"]