PREHEAT oven to 350F (180C). Lightly butter or spray an 8-in. (2-L) square baking dish. In a small bowl, stir flour with salt. In a medium bowl, using an electric mixer, beat butter with sugar for 1 min. Beat in eggs and vanilla. Gradually beat in flour mixture. (If you don’t have a mixer, use a wooden spoon. Beat butter with sugar for 2 min. Beat in eggs and vanilla. Gradually beat in flour mixture.) Stir in pecans and chocolate chips and Skor pieces just until evenly distributed. Turn into prepared baking dish and smooth the top as best you can.
BAKE in centre of preheated 350F (180C) oven until top is deep golden and squares come away from sides of pan, 30 to 35 min. Remove dish to a rack to cool slightly.
WHILE still warm, cut into 16 squares or 32 bars. Store in an airtight container between layers of waxed paper at room temperature. They will keep well for 3 days or freeze up to 2 months. Just before serving, drizzle top with a little caramel sundae sauce.