1. Heat oven to 350°F. Unroll pastry; place in bottom and up sides of 9-inch springform pan.
2. Beat butter in medium bowl; add eggs and rum extract, blending well. Stir together sugar, flour and salt; beat into butter mixture. Stir in walnuts and butterscotch chips; spread in bottom of crust. Fold edges of crust loosely over filling, if desired.
3. Bake 45 to 50 minutes or until golden brown. Cool 10 minutes on wire rack; remove side of springform pan. Cool an additional hour. Best if served slightly warm. Cut into wedges and serve with vanilla ice cream, if desired. 12 to 16 servings.