Prepare a baking sheet with either aluminum foil or parchment paper.

Heat the saucepan over medium heat, put the butter, sugar, water and salt, stir until the sugar dissolves in the pan and the butter melted.

Continue stirring until it comes into boil then remove from the heat and add vanilla extract and cashews.

Transfer the mixture into the separate pan and set aside.

Melt the white chocolate in the microwave oven.

Stir frequently in order not to overheat.

Remove from the heat when it is already cooked then pour the white chocolate on top of the toffee candy spread evenly in the layer.

Use the remaining cashews to top the mixture, sprinkle on top and set aside to let it cool.

Refrigerate to thicken.

Once firm invert the toffee and spread the remaining white chocolate at the back portion of the toffee.

Refrigerate for an hour.

Once harden break the toffee into pieces and store in a container.