1 box confectioners' sugar
1/4 c. cream or milk
1/2 c. cocoa
1 tsp. vanilla
1 stick butter

Put ingredients into a glass bowl, adding butter last - do not mix. Microwave on High for 2 1/2 minutes. Mix until most sugar lumps dissolve. Then add any of the following options:

1 c. peanut butter
1/2 c. chopped walnuts
1/2 c. marshmallow cream - fluff
1/2 c. mini marshmallows