03Pour the mixture into your prepared baking pan and press down evenly. Bake in the oven for 25 minutes or until golden brown.
04Melt 1/4 cup of butter in a heavy medium saucepan. Add in 1/3 cup each of granulated sugar, brown sugar and corn syrup, as well as 1 tablespoon of water and 1/4 teaspoon table salt. Add in 1/2 cup chopped cashews. Bring to a boil, stirring constantly. Let it boil, stirring occasionally for 5 minutes. Reduce the heat if it turns into a rolling boil. Take it off the heat and add in 1/4 cup whipping cream and 1 teaspoon vanilla.
05When the crust is ready, pour the butterscotch mixture evenly over the top and bake for another 12 minutes.
06Let it cool in the pan on a rack. We want the top to be tacky for the salt but not so hot that the salt just melts in.
07Sprinkle with 1/2 teaspoon of salt evenly over the surface. I like sea salt because of the large granules. You can also use kosher salt.
08When it is completely cool, just lift them out by the foil. Peel the foil off and slice into bars.