3/4 box 10X sugar
5 tbsp. milk
Pinch of salt
4 squares unsweetened chocolate
4 tbsp. butter (stick)
1 tsp. vanilla

Mix together sugar, milk and salt until smooth. Melt chocolate and butter. After chocolate is melted, add to sugar mixture plus vanilla, stirring off and on for about 1/2 hour. If thick, add a little more milk until it's the right consistency to spread.