1/2 c. butter
1/4 c. white Karo syrup
1 c. brown sugar
1/2 tsp. liquid butter flavor
1/2 c. (unpopped) popcorn

Stir above ingredients, except popcorn, together in a medium saucepan. Bring to a boil for 5 minutes on medium heat. Pop corn in hot air popper, put into large roasting pan. Pour syrup over popcorn and mix. Bake in oven at 225 degrees for 15 minutes, stirring every 5 minutes. (Use an oven mitt, this stuff gets hot!). Remove from pan, put in large bowls (not plastic) and break it up as it cools. Nuts may be added before baking.