betty mae's caramel corn

Honest to goodness I have never come across a better recipe for caramel corn. It's my grandma's recipe.

betty mae's caramel corn (my grandma)
2 cups brown sugar
1/2 cup Karo syrup
1/2 pound butter
2 bags butter microwave popcorn, popped and loose kernels removed
1/2 teaspoon baking soda
dash of salt

Cook brown sugar, Karo syrup and butter on low heat stirring constantly until mixture just starts to bubble.  Do not boil.  Add a dash of salt and 1/2 teaspoon baking soda and stir until mixed well and the color the the caramel lightens a bit.   Pour over popcorn.  Spread on a greased baking sheet.  Bake for 1 hour at 200 degrees.  Stir occasionally.  Let cool.  Break pieces apart and enjoy!