Spray inside of measuring cup with nonstick cooking spray. In a medium saucepan, over medium-high heat, add corn syrup, sugar, and salt. Cook on stove until the temperature reaches 310 degrees F. on a candy thermometer. Once the mixture reaches 310 degrees F, take off the stove; add the baking soda, cashews and butter, working quickly and stirring constantly.
The mixture should stay an opaque color. On a nonstick tray sprayed with nonstick cooking spray, pour in the mixture and spread with wooden spoon. Cool for 1 1/2 hours.
Place 2 scoops of vanilla ice cream on each dish and garnish with broken pieces of cashew crunch.
A silicone mat would work best to avoid a sticky clean-up.