Prepare fruit by removing and discarding strawberry stems. Crush fruit.
Use dry measuring cup to measure exact amount of prepared fruit into the sauce pan.
Measure the exact amount of sugar into large bowl. (Do not reduce sugar in recipe since that will result in set failures.)
Combine 1/4 cup sugar from measured about and 1 package Sure Jell for Less or No Sugar Needed Premium Fruit Pectin in small bowl. Stir into fruit. Add 1/2 tsp butter to reduce foaming, if desired.
Bring mixture to full rolling boil (a boil that doesn't stop bubbling when stirred) on high heat, stirring constantly.
Stir in remaining sugar. Return to full rolling boil and boil exactly 1 minute, stirring contantly. Remove from heat. Skim off any foam with metal spoon.
Ladle immediately into prepared jars, filling to within 1/4 inch of tops. Wipe jar rims and threads. Cover with two-piece lids. Screw bands tightly.
Place jars on eleveated rack in canner. Lower rack into canner. "Water must cover jars by 1-2 inches. Add boiling wter, if needed.) Cover; bring water to gentle boil. Process for 10 minutes, adjusting processing time for altitude, if necessary.*
Remove jars and place upright on a towel to cool completely. After jars cool, check seals by pressing centers of lids with finger. If lid springs back, lid is not sealed and refrigeration is necessary.
Let prepared jars stand at room temperature for 24 hours. Store unopened jams and jellies in a cool, dry, dark place for up to 1 year. Refrigerate open jams and jellies for up to 3 weeks.