Preheat the oven to 350F. Spray a 13x9-inch baking pan with non-stick cooking spray.

In the bowl of a mixer, combine the flour, butter, brown sugar and salt. Beat until it resembles coarse crumbs. Press into the prepared pan. Bake in the preheated oven for 15 minutes, or until golden brown. Sprinkle the chocolate chips over the hot crust immediately after removing from the oven. Let sit for 5 minutes, or until the chocolate chips turn glossy and soft. Use a spatula to spread the chocolate evenly. Set aside.

In a 2-quart saucepan, combine the butter, brown sugar, corn syrup and vanilla. Cook over medium heat, stirring frequently. Bring to a boil. Stop stirring and allow to boil for 4 minutes. Gently pour over the chocolate layer. Cool completely. Refrigerate until the chocolate and caramel are set, about 1 hour.

Bring to room temperature to cut into 2x1-inch bars.