http://www.branappetit.com/2011/08/03/no-bake-bars/ 
YumYum

No-Bake Bars

1/2 cup (1 stick) butter
1/4 cup Cocoa Powder
2 cups Sugar
½ cup Milk
3 cups Oats (Old Fashioned or Quick)
½ cups Creamy Peanut Butter
1 teaspoon Vanilla Extract

Line an 8×8 pan with waxed paper and set aside.  In a large sauce pan, bring butter, cocoa, sugar, and milk to a hard boil, stirring frequently. Boil for a minute and a half, stirring constantly. Remove from heat and add oats, peanut butter, and vanilla. Mix well. Immediately transfer the mixture to the prepared pan, spreading  to an even thickness. Allow to cool completely before cutting