Preheat oven to 250 F.
Pour the hulless popcorn into a large roasting pan that has been lightly sprayed with non-stick cooking spray.
In a medium-sized saucepan, bring butter, sugar, salt and syrup to a gentle boil over medium high heat. Boil for 5 minutes, stirring constantly.
Remove from heat and stir in baking soda. The caramel will foam up a bit and lighten in color. Stir to combine.
When well blended, pour caramel over the hulless popcorn and stir gently to coat all pieces.
Bake the caramel corn in a 250 F oven for 1 hour, stirring well every 15 minutes.
Remove from oven and stir once more; allow to cool. Popcorn stores well in an airtight container.
