1Place the popped popcorn into two shallow greased baking pans. Set aside.
2Preheat the oven to 250 degrees F. Combine the brown sugar, syrup or honey,butter in a saucepan. Bring to a boil. Boil for 5 minutes while stirring constantly.
3Remove from the heat, and stir in the baking soda and vanilla. The mixture will be light and foamy. Immediately pour over the popcorn in the pans, and stir to coat. Don't worry too much at the point about getting all of the corn coated.
4Bake for 1 hour, removing the pans and giving them each a good stir every 15 minutes. Line the counter top with waxed paper. Dump the corn out onto the waxed paper and separate the pieces. Allow to cool completely, Then store in airtight containers or resealable bags.