Line a 12 x 17" sheet pan with parchment paper, leaving enough on the sides to be able to lift the entire pan of caramel out of the pan. Set aside.
In your heavy duty pot, combine evaporated milk, butter, heavy cream, baking soda, salt, and lecithin. Turn heat to medium.
Stirring constantly, bring mix to 180F. When you reach 180F, turn off heat and let liquid mix sit undisturbed for 20 minutes.
While the liquids are resting combine molasses and pumpkin spice. Stir the pumpkin spice into the molasses until it is dissolved. Set aside.
Once your liquids have rested for 20 minutes, add in sugar and corn syrup. Turn heat to medium and bring it to a boil. After your caramel beings to boil, you may increase heat to medium high. Stir the entire time this is cooking.
When caramel reaches 240F, add in molasses and pumpkin spice mix. The temperature will drop. Bring the temperature back up to 242F.
When the temperature reaches 242F, turn off heat and stir in pecans. Pour caramel on prepared lined sheet pan.
Let caramel cool for a minimum of 4 hours before making nougat to layer on top. If you are only making the caramel, cover with parchment and foil after 30 minutes. Cool overnight before cutting.