1/2 pound (2 sticks, or 1 cup) butter
1 cup firmly packed light brown sugar
1 1/4 teaspoons kosher salt
2 1/2 cups all-purpose flour
11 ounces butterscotch chips
3/4 cup light corn syrup
1 Tablespoon plus 1 teaspoon water
2 cups roasted salted whole cashews
Preheat oven to 350°F.
Spray a 9x13 pan with cooking spray.
Using two sheets of parchment paper, line the pan's width and length, creating a parchment "sling."
Spray parchment paper with cooking spray.
Beat together the butter, brown sugar, and salt for two minutes, then add the flour and mix on low until it just holds together.
Lightly press dough evenly into the prepared pan and prick with a fork.
Bake for 30 minutes, until the crust is a golden color.
In a heavy saucepan over low heat, stir together butterscotch chips, corn syrup, and water.
Stir until mixture comes to a simmer and butterscotch chips are melted.
Pour over crust.
Sprinkle cashews over the butterscotch caramel.
Bake for 5 minutes.
Cool completely on a wire rack.
After cooling, remove from pan and use a very sharp knife to cut into bars.