Combine first three ingredients and boil, stirring constantly, until it thickens and is the color of a brown paper bag. This will take about 10-12 minutes of constant stirring. The consistency will go through about four stages in looks. Be careful not to overcook or it will taste scorched.
Pour over a lightly greased 12 x 18 cookie sheet, spreading it as fast as you can into the pan. Sprinkle chocolate chips over hot candy and let melt. Spread the chocolate over the candy.
It's tricky to get it just the right color. Too light and it doesn't have the toffee consistency and flavor, too dark and it tastes burned.
BE CAREFUL HANDLING CANDY WHEN HOT BECAUSE IT IS VERY, VERY HOT!