Preheat the oven to 375 degrees.
Lightly grease a large, non-stick, cookie sheet (I use a dark, airbake cookie).
In a medium bowl, cream the butter, brown sugar, and sugar with a hand held mixer until combined well.
Add the egg and pure vanilla extract, beat until creamy and fluffy.
Next, add the flour, baking soda, and salt.
Mix on low speed until just combined. The dough should be stiff.
Stir in chocolate chips and toffee.
Drop by rounded 1/8 cup portions onto lightly greased cookie sheet.
Bake 8-10 minutes until the edges are lightly browned, the top is just starting to brown, and the center is still gooey and appears slightly raw.
Take the cookie sheet out of the oven and allow the cookies to cool directly on the baking sheet to finish baking for at least 10 minutes before serving.
Notes: These cookies are best served the day they are baked but can be stored in an airtight container for up to 3 days. I highly recommend reheating them in the microwave for 10-20 seconds before serving.