Prepare a work surface (kitchen counter) by laying out a 4 feet long piece of parchment paper. After popping the popcorn, transfer it to a bowl. Lift the popcorn with your hands and shake the bowl lightly so the unpopped kernels fall to the bottom. Lift the 4 quarts of popcorn out of the bowl and transfer to a large brown paper grocery bag.

Place the butter in a large (2 quart) microwave safe bowl and microwave on high power for one minute or until the butter is melted. Add the corn syrup and stir well to combine. Add the molasses, brown sugars, cinnamon, ginger, allspice, cloves and salt. Stir until everything is well incorporated. Place in the microwave and heat on high power for 2 minutes. Stir then return to the microwave for 1 minute. The mixture should be bubbling up furiously by this point. Remove bowl and stir then return to the microwave for another minute. Repeat this cooking for one minute and stirring two more times.

Remove the bowl from the microwave and stir in the vanilla and baking soda. Stir until all of the baking soda is well incorporated.

Pour the hot mixture over the popcorn in the bag. Fold the top of the bag down once and shake, shake, shake to distribute syrup through the corn. Microwave on high power for 1 minute. Remove the bag and hold it at the folded down top and one of the bottom corners. You may need to use a pot holder as the bag will be hot. Shake well the return to the microwave for another minute.

Repeat cooking and shaking two more times for a total of 5 minutes. Turn the popcorn out onto the prepared parchment paper. Allow to cool completely.

Store in an airtight container. The caramel corn will keep well for 1-2 weeks.