I agree with whoever said a cube of butter is 1/2c. You can buy a pound of butter & it often comes divided into 4 prewrapped cubes (wrapped in paper that marks off 8 Tbs. ). So for that recipe there would be 1/2 TBS per ea cup of popcorn. Definitely not non-fattening...but sounds nummy! If you want lower fat you could probably double the popcorn or half the carmel recipe or something like that.