Preheat oven to 250 degrees. Have a large baking sheet ready. (Jan’s Note: I used a 17″ x 12″ sheet pan. Be sure your baking sheet is large enough to fit the puffs so that you can comfortably stir them without the puffs falling out of the sheet.) In a medium large saucepan, melt butter, brown sugar and corn syrup. Stir to dissolve sugar and bring to a boil, stirring gently. Cook for exactly 2 minutes, stirring occasionally. Add baking soda. The mixture will quickly foam up and double in size. Stir gently to combine baking soda then immediately pour caramel mixture evenly over the corn pops. Gently stir until most the pops are evenly coated. Place puffs in the oven for 45 minutes. Important! Stir every 15 minutes to coat, as caramel sauce will pool in places on the bottom of the sheet pan. When done, remove from oven and stir again to separate the pieces. Let cool and enjoy!