Preheat oven to 350°F (177°C). Grease a cast-iron skillet.
Beat softened butter, egg and water in large bowl until combined. For best results, use an electric mixer. Slowly add Cookie Mix and continue mixing until dough forms. Gently stir in BUTTERFINGER® Baking Bits (reserving a tablespoon for sprinkling), butterscotch morsels and chopped pecans until evenly distributed.
Press dough into cast-iron skillet into an even layer. Sprinkle with sea salt. Bake cookie for 20-25 minutes, until golden brown. Remove from oven and let cool for 5 minutes. Cut into wedges and serve warm with a scoop of vanilla ice cream.