Preheat oven to 350°F. Grease a 9×13 inch baking pan.
Add butterscotch chips and butter to a medium saucepan over medium low heat. Melt. Stir in graham cracker crumbs and pecans. Press ½ of mixture into prepared baking pan.
Beat cream cheese until fluffy. Beat in sweetened condensed milk, vanilla and egg. Pour over crumbs. Top with remaining crumbs.
Bake for 25 minutes. Cool to room temperature then chill in the refrigerator before serving.