Margaret Smith is my grandmother's dear friend from Kingstree, South Carolina.
Arrange half of graham crackers in a single layer on a 15- x 10 inch baking sheet.
Bring granulated sugar and next 2 ingredients to a boil in a saucepan over medium heat, stirring constantly. Boil 1 minute, stirring constantly. Remove from heat.
Stir in eggs, next 3 ingredients, and 1 tsp. vanilla; pour mixture over graham crackers. Top with remaining graham crackers.
Beat melted butter, next 2 ingredients, and remaining 1 tsp. vanilla with an electric mixer until smooth; spread over graham crackers. Chill 2 hours or until set. Cut into bars.