Add the butter to a small saucepan over medium heat and let it melt.

Add the sugar and cashews.

Stir the mixture frequently (it burns easily so watch it closely) until the sugar melts and caramelizes over the nuts. Once all the sugar has melted and coated the nuts, they're done.

Spread them onto a plate or piece of parchment paper so they don't all stick together. Some will clump together, which is fine.

Allow them to cool then store them in a sealed container.