Preheat oven to 350°F. Lightly spray a 13” x 9” baking pan with cooking spray.
In a bowl using an electric mixer, butter and Splenda Brown Sugar Blend on medium speed until blended. Add egg yolk and mix until blended. Add flour and salt; beat on low speed until blended.
Press mixture into bottom of prepared pan.
Bake for 12—14 minutes or until golden. Cool in pan on a wire rack.
To make the toffee:
In a saucepan, combine butter, Splenda Brown Sugar Blend, corn syrup, evaporated milk, and vanilla extract. Cook over low heat, stirring constantly, until sweetener dissolves.
Bring mixture to a boil over medium heat and cook until a candy thermometer reaches 265°F (about 10 minutes). Pour mixture over crust and spread evenly. Bake 10 additional minutes. Cool 5 minutes on a wire rack.
To make the topping:
In the top of a double boiler, combine chocolate squares and Splenda Brown Sugar Blend. Heat until chocolate melts and mixture is smooth. Drizzle or spread over toffee. Sprinkle with chopped pecans.
Cool completely on wire rack. When chocolate is firm, cut into bars or triangles.
