Line a baking sheet with parchment paper and set aside.
Add the butter to a small pot and melt on low heat before adding the sugar and salt.
Cook on low heat for 5-7 minutes stirring in the same direction every 30 seconds until the mixture turns a glossy amber color.
Remove from the heat and pour the mixture onto the prepared baking sheet.
Use a rubber spatula to spread it into a thin rectangle.
Sprinkle the chocolate chips all over the warm toffee and let sit for 5 minutes to melt.
Use an offset spatula to spread the chocolate into an even layer all over the top.
Sprinkle the chopped walnuts and let the toffee set until the chocolate is hardened.
Crack into pieces and enjoy.
