In a heavy 2 1/2 –qt. saucepan over low heat, melt the butter. Then, add sugar, brown sugar, water and molasses, stirring until the sugar dissolves. Raise the heat to medium and attach a candy thermometer to the side of the pan.
Cook, stirring slowly but constantly, until the temperature reads 290˚F (about 15 min.). Remove from heat immediately and remove the thermometer.
Stir in the cinnamon. Next, pour the mixture all at once onto your buttered baking dish. Do not scrape the bottom of the pan.
Let the candy harden for one minute, then sprinkle the chocolate chips on top and let soften. Using a rubber spatula, spread the chocolate evenly over the toffee.
While the chocolate is still warm, sprinkle the pecans over the chocolate and place the whole thing in the refrigerator. Break into desired pieces and store in an airtight container.