Line a sheet pan with parchment paper and set it close by you.
Place the walnuts, sugar, butter, and salt in a non-stick skillet set over medium heat. Cook, stirring frequently, until the sugar melts and becomes syrupy on the bottom of the skillet. Continue stirring constantly for 4 to 5 minutes making sure the syrup get hot enough to bubble.
Remove the skillet from the heat and tip the walnuts onto the parchment paper.
With a fork, spread the walnuts out in one layer, breaking them apart so they are not touching each other. Allow the walnuts to cool, then transfer to a dish.
Use immediately or keep in an airtight container in a cool cupboard.
Notes
Light or dark brown sugar works with this recipe.
Stir the mixture frequently and adjust the heat if needed to keep from scorching or burning.
Work very quickly with a fork to spread and separate the nuts from sticking together.
Do not touch the hot nuts with your fingers!
Variations
Cinnamon Spice Walnuts: 1 to 2 teaspoons cinnamon, ½ teaspoon ground nutmeg, ¼ teaspoon allspice, and a pinch of ground cloves.
Sweet and hot: add ½ teaspoon cayenne pepper and ½ teaspoon smoked paprika.