Clean and sterilize 8 half-pint canning jars and lids in simmering water for 10 minutes.

Score the bottom of each peach with an 'X' and blanch in boiling water for 30 seconds.

Transfer peaches to an ice bath, peel and crush until you have about 4 cups of finely chopped fruit.

Measure 5.5 cups of granulated sugar in a separate bowl.

In a large pot, combine crushed peaches, lemon juice and pectin; stir well. Add butter if using.

Bring mixture to a full rolling boil while stirring constantly; add sugar and boil hard for 1 minute.

Skim any foam from the top of the jam for a smoother texture.

Ladle jam into jars, leaving 0.25 inches of headspace, then seal with sterilized lids.

Process jars in a boiling water bath for 10 minutes.

Allow jars to cool for 5 minutes on a towel and then leave undisturbed for 12-24 hours.

Check seals by pressing the center of each lid; if it pops back, store that jar in the refrigerator.