Preheat the oven to 350 degrees.

In a large bowl cream the butter and brown sugar until smooth. Add in the flour and mix well.

Press the cookie crust into the bottom of a 9 x 13 pan. Bake for 20-25 minutes or until the cookie begins to brown. Remove from the oven.

Meanwhile, pour the sweetened condensed milk and butter in a medium saucepan over medium high heat. Heat for 5 minutes, stirring frequently. Remove from heat and stir in the salt.

Pour the milk mixture over top of the baked cookie crust and bake for 12-15 minutes or until the layer is set.

Remove from oven and sprinkle the chocolate chips over top. Bake for 2 minutes.

Remove from oven and smooth the melted chocolate chips over top of the cookie bars. Sprinkle with toffee bits.

Allow the cookies to cool completely on a wire rack. If the chocolate isn't hardening, refrigerate for 10 minutes.

Cut into bars and serve.