When ready to bake, preheat oven to 350°F and line a baking sheet with parchment paper. Set aside.
In a medium bowl, mix together the flour, cornstarch, and salt. Set aside.
In a separate, larger bowl, cream together the butter and powdered sugar with an electric mixer. Add vanilla and mix until combined.
Gradually add dry ingredients to butter mixture, stirring to combine. Add butterscotch chips and toffee bits and stir.
Lay a sheet of plastic wrap onto a countertop or work surface. Place dough on top of plastic wrap and form into a log about 2.5 inches in diameter. Wrap and chill until firm, 1 to 2 hours.
Unwrap dough and cut into 1/4-inch slices. Arrange slices 2 inches apart on prepared baking sheet and bake until lightly browned on edges, 10-12 minutes.
Let cool on sheet 2 minutes before removing to a wire rack to finish cooling. Enjoy!
