Preheat oven to 175°C and line 3 baking trays with baking paper.
In a small saucepan over medium heat, melt the butter. Once melted continue to stir and bring the butter to a boil until browned. The butter will foam and turn a dark amber colour. Once browned remove from the heat and set aside to cool for 20 minutes.
In a large bowl mix the butter and sugar together. Add the eggs and vanilla and mix together until smooth.
Add the salt, bicarbonate of soda and flour to the biscuit mixture. Stir until well combined. Then add the chocolate chips and cashews until combined. Optional - keep ¼ cup of the chocolate chips aside to place 2-3 on top of each ball of biscuit mixture before baking.
Scoop 1½ tablespoons of mixture into balls and lightly flatten on the prepared tray 2 inches apart. Bake for 10 minutes or until the edges are lightly browned. Transfer cookies to a wire rack to completely cool. Then EAT!