I remember helping my mother make these quick and easy to make bars when I was young. They were quickly gobbled up by my brothers if Mom wasn't watching. These bars are really yummy and taste like fudge.
Cook the first 4 ingredients in a saucepan over medium heat for five minutes, stirring constantly. Remove from heat and add 2 teaspoons of vanilla.
Add 3 cups of graham crackers and 2/3 cups of finely chopped walnuts to the mixture, stirring well. Put mixture into an ungreased 9 x 13 pan and place in the fridge until fully cooled. These bars can be topped with any icing you fancy. I usually make a thin butter icing.