Combine butter, brown sugar and light corn syrup in a 2-quart saucepan and cook on medium heat until mixture has melted.
Once mixture has melted add the baking soda. (Note This will cause the mixture to foam).
Pour Old Dutch® Puffcorn into a large roaster pan.
Pour caramel mixture over the Puffcorn and stir until mixed.
Place in oven at 250° for 45 minutes, stirring at least every 10-15 minutes. Please pay close attention at this time as oven temperature variance may affect final product.
Remove from oven, pour onto wax paper and break apart.