Addictive, crunch caramel popcorn.
Preheat the oven to 200 degrees Fahrenheit. Spray a large cookie sheet with non-stick cooking spray. Pop the popcorn and remove any un-popped kernels. Put popcorn in a large bowl.
Combine the sugar, butter, syrup, cream of tartar, and salt in a medium sauce pan over medium heat. Stir constantly and bring to a boil. Boil for 5 minutes.
Pour caramel over the popcorn and mix until popcorn is coated. Pour onto the cookie sheet.
Bake for 1 hour, stirring every 20 minutes. Allow to cool and then break apart into desired sizes. Store in an air-tight container.