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 over medium heat. Stir frequently until the sugar starts to melt and turns syrupy. Once that happens, stir constantly for another 4 to 5 minutes, making sure the syrup gets hot enough to bubble and coat the walnuts.If the sugar looks dry or clumpy and won’t melt smoothly, you can add 1 to 2 tablespoons of water to help it along, it’ll evaporate as the syrup cooks.
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.