Preheat oven to 375 degrees.
In a large bowl cream together butter and sugars until well blended. Add egg and vanilla.
Add dry ingredients and beat until well blended.
Toss in chocolate chunks, nuts and toffee; fold into batter.
Chill batter in fridge for about 30 minutes.
Scoop out by the heaping tablespoon, roll into balls and set on a baking sheet lined with parchment or a silpat.
Bake for 8-10 minutes (check after 8 minutes); cookies are done when they are browning on the bottom. Allow to cool for 5 minutes on the pan before moving to a wire rack. Make sure they are cool enough that they are set so they do not melt through the wire rack.
Once cooled completely, take two cookies of equal size and scoop around 1/3 cup onto the flat side of one. Gently smush down into an even layer and top with the other cookie.