Preheat oven to 350 degrees. Fit piecrust into a 9-inch pie plate, fold edges under, and crimp.
Whisk together brown sugar and next 4 ingredients in a large bowl until smooth. Whisk in melted butter; stir in pecans and butterscotch morsels. Pour mixture into piecrust.
Bake at 350 degrees for 50 minutes or until set and slightly puffed. Cool completely on a wire rack.
To make it extra yummy, warm slightly and serve with whipped cream or ice cream!