Add strawberries to a large stockpot and start mashing up over high heat. Add SURE JELL and butter and bring to a hard boil.

Add the sugar all at once and stir to mix and dissolve and bring back to a roiling boil.

Time for 1 minute and then do a spoon check as described above.

Pour into prepared jars to 1/8" from the rim. Wipe clean and then put lids and screw caps on the jars.

Turn over on a clean towel for 5 minutes and then turn upright and let rest for 24 hours. Store any unsealed jars in the refrigerator.