Using a food processor, grind the graham crackers to a fine crumb. (If you don't have a food processor, you could put the crackers in a sealable plastic bag and use a rolling pin to crush them.)
3 cups graham cracker crumbs
In a large bowl stir together the crumbs, 1 cup melted butter, sugar, peanut butter, and vanilla. It may be difficult to mix at first but will come together to be a thick dough.
1 cup unsalted butter, 2 1/2 cups powdered sugar, 1 cup creamy peanut butter, 2 teaspoons vanilla extract
Press the dough into a 9 by 13 inch pan that has been sprayed with non stick spray.
In a microwave safe bowl, combine the remaining 8 tablespoons butter and chocolate. Cook for 1 minute, at half power, stir very well. Microwave in 15 second intervals stirring very well in between until smooth. Pour over bars. Chill in the refrigerator for 1 hour before cutting.
1 cup milk chocolate chips, 8 tablespoons unsalted butter