Carmel Corn

3 Quarts popped popcorn, keep warm in 225F oven Over med. heat cook the following to boiling, stirring. Then cook 5 min. w/o stirring: 1/2 C butter 1/2 C Karo syrup 1/2 C brown sugar 1/2 t. salt Quickly add:1/2 t. vanilla and 1/2 t. baking soda. Stir. Add to warm popcorn. Stir. Cook 1 hour, stir every 15 min. If the sugar cracks, it cooked too warm or too long.