Mix the dry ingredients (flour through salt) together in a bowl and set aside.
Cream the butter and sugars together until light and fluffy, about five minutes. Beat in the eggs and the vanilla. Reduce the speed to stir (low) and slowly add in the dry ingredients until combined. Mix in the chocolate chips, toffee, and hazelnuts, stirring just until combined. Cover and refrigerate for 24-36 hours.
Preheat the oven to 350 degrees and line baking sheets with parchment paper. Scoop the dough in 1.5 T portions (I used a medium cookie scoop) onto the prepared cookie sheets.
Bake for 12 minutes for lightly golden and chewy cookies or 18 minutes for dark and crunchy cookies. Allow to cook on cookie sheet for 5 minutes and then move to a wire rack to cool completely. Store in a tightly covered container.