In Hawaii, there are fierce competitions to see who makes the best shortbread - many aunties swear they make the best one, and some have taken their recipes and "secret ingredients" to the grave with them. I adapted this recipe from a friend who shared her secret with me.
Cream together sugar and butter. Add flour in parts, making sure it is well blended before adding more flour.
Spread onto ungreased jelly roll pan (12"x17") and smooth with rolling pin (1/4" thickness).
Bake at 250 degrees for 1-1/2 to 1-3/4 hours. If using 9"x12" jelly roll pan (1/2" thickness), bake for 2 to 2-1/2 hours.
Melt chocolate chips in the microwave. Pour over hot shortbread (immediately after taking out of oven) and spread with frosting spatula.
Immediately sprinkle toffee bits and chopped pecans evenly over chocolate. Cut into bars or squares using a sharp knife and let cool, making sure they are not touching while chocolate hardens. Do not refrigerate.