Cooked Strawberry Jam

Directions

1. Wash, hull and halve berries. Crush one layer at a time and measure 5 3/4 c. into a 6-qt kettle. Stir in lemon juice. Add in package of pectin and stir thoroughly to dissolve. This will take several min. Stir down sides of pan and crush any remaining lumps of pectin.
2. Place pan on high heat. Bring to a boil, stirring constantly to prevent scorching. Add in sugar gradually, then butter, mixing well. Continue stirring and bring to a full rolling boil (a boil which can't be stirred down). Boil hard exactly 4 min, stirring constantly to prevent scorching.
3. Remove jam from heat. Skim foam from top. Pour into warm, sterilized jars, wipe top and threads of jar. Apply warm lid and screw band. Twist screw band down tight. Process in boiling water bath 5 min. Start counting time when water comes to a boil.