Preheat oven to 375 degrees.
Coat an 8-x-8-inch baking pan with cooking spray. Set aside.
In a medium-sized mixing bowl, stir together flour, baking soda and salt, and set aside.
Using a standing or hand-held mixer on low speed, cream the butter, cream cheese, brown sugar and white sugar until smooth. Add egg and vanilla, and beat until well incorporated. Add the dry ingredients and stir just until combined.
Transfer the batter to the prepared baking pan and sprinkle the toffee candy over the batter. Bake for 20 minutes, or until a toothpick inserted in the center comes out clean.
Let cool completely in the pan on a wire rack. When cool, cut into bars and serve.
Source: Cook Yourself Thin