4. Once temperature reaches 300 degrees, remove from heat. Immediately stir in vanilla and pour into prepared baking dish. Even spread toffee mixture and let sit for several minutes until the toffee starts to harden on the top. The toffee will turn opaque as it cools.
5.When the majority of the toffee is opaque, sprinkle chocolate chips evenly over the toffee. Cover dish with aluminum foil and let sit for 4-5 minutes to help melt the chocolate.
6. Remove the foil, and spread the melted chocolate evenly over the toffee. Top with flaked salt and crushed pecans. Cover again and place in the refrigerator to further set for 1-2 hours.