In a heavy 2 quart sauce pan over medium-high heat, mix:
1 cup sugar
1 cup butter
1/4 cup water
Stir constantly and cook till mixture reaches 300 degrees on a candy thermometer.
Immediately pour toffee onto parchment on a heat resistant surface. (I line a cookie sheet with parchment and set it on a wire cooling rack.)
Spread toffee to about 1/4 thickness. Work FAST! The toffee cools quickly and becomes unspreadable pretty quick.
Let toffee cool 1-2 minutes then sprinkle with:
1/2cup -1 cup of chocolate chips.
The heat of the toffee will melt the chocolate chips in a a few minutes. Once chocolate it melted, spread it evenly across the top of the toffee.
Sprinkle with chopped pecans if desired.
Let cool completely (until chocolate is hardened) -stick it in the fridge to speed things up if you want.
Break into bite size pieces.
Try not to eat he entire batch immediately. ;-)