In small bowl mix together flour, baking soda and salt.

In stand mixer or using mixer cream butter and sugar until fluffy. Add in vanilla and egg and mix on low just until incorporated. Add dry ingredients to butter mixture in three parts mixing until combined; scraping the bowl and the beaters.

Stir in toffee crumble and cashews. Cover and refrigerate for several hours up to overnight.

Preheat oven to 350 degrees. Using 1 1/2 tablespoon cookie scoop place on cookie sheets a couple inches apart. Bake 13-14 minutes. Do not over bake. Cool on cookie sheets for 10 minutes before carefully placing on cookie cooling racks.