Place popped corn in a large roaster pan. Preheat oven to 200 degrees. Boil sugar, syrup, butter, salt and creme of tartar for 5 minutes. Remove from heat and add soda. Stir well then pour over the corn mixing well to coat all the kernels. Place in oven for 1 hour, stirring ever 15 minutes. Then pour out on a smooth surface and spread to cool. This should be done quickly so caramel doesn't stick to the roaster. Store in airtight container.
~This will keep for a couple of weeks very nicely.
From: Glorious Grub Cookbook By. Joan Stewart