Caramel Corn

This recipe is from my Great Aunt, Nan. She was a terrific cook and I grew up watching her making meals for the American Legion. Below are the directions exactly as she wrote them out for me. I will include some additional instructions in parentheses, just to keep things clear.

INGREDIENTS:
2 C Packed brown sugar
1 C Butter
1/2 C Karo light corn syrup
1 tsp. Salt
1 tsp. Baking soda
6 Qts. Popcorn popped, I use an air popper that Beep has had since college : )
Peanuts optional, I also like to add almonds

PREPARATION:
Boil 5 minutes remove from heat and add 1 teaspoon soda. (In a heavy bottom pan heat the first four ingredients, stirring constantly and bring to a full boil, then continue to boil for 5 minutes). Pour over 6 quarts of popcorn. Mix thoroughly spread on buttered cookie sheet. (I spray a deep foil roasting pan with non-stick spray, fill with popped popcorn and nuts if desired, then pour the hot caramel over and mix in the disposable pan). Bake at 200 degrees 1 hour. Stirring every 15 minutes. Remove from the oven cool. (I pour the corn onto a large surface lined with parchment paper to cool. If you leave it in the pan to cool the caramel will collect in the bottom of the pan and you will end up with strange chunks.) Store in tightly covered container.
Aunt Nan also wrote on the back of the recipe card: I mix it in a roaster and then put it back in every 15 minutes to mix. When you put your soda in beat until it is foamy.