Sift together the flour, baking soda, and salt; set aside.
In a medium bowl, cream together the melted butter, brown sugar and white sugar until well blended. Beat in the vanilla, egg, and egg yolk until light and creamy. Mix in the sifted ingredients in three batches until just blended. Fold in the chips, toffee and pistachios by hand.
Rolls 2 tablespoons of dough into a ball that is slightly taller than wide and place on a plate or tray. Cover tightly and chill for at least 2 hours, but overnight for best results (I’ve refrigerated for up to a week).
Preheat oven to 375 degrees. Line cookie sheets with silicone baking mats (or parchment paper); set aside.
Place cookie dough onto the prepared cookie sheets, about 2 inches apart.
Bake for 8 minutes or until edges are barely golden (will look underbaked). Cool on baking sheets for 10 minutes before transferring to wire racks to cool completely. Store at room temperature in an airtight container.