1. Crush strawberries. This is easiest with an immersion blender, or for soft strawberries (such as frozen, thawed berries), a potato masher
2. Pour strawberry mash into a large (at least 4 quart) pot, and stir in powdered pectin and lemon juice until pectin is dissolved.
3. Add butter (optional, but highly recommended) and heat over medium heat to bring to a full boil that can’t be stirred down.
4. Stir in sugar
5. Continue stirring until sugar is dissolved.
6. Bring to a full, rolling boil again.
7. Set a timer and continue boiling for 1 minute.
8. Remove from heat and skim off the foam. Save it in a bowl to use fresh
9. Ladle strawberry jam into sterile jars, wipe rims, add lids, and screw down rings firmly. 

Canning Instructions:

1. Insert rack into bottom of water bath canner, and fill your with 5-6 inches of hot water 
2. Lower jars gently into canner, taking care to space them so they do not touch.
3. Add more water if necessary so that it reaches at least an inch over the top of the jars.
4. Cover, and bring to a rolling boil.
5. Boil for 10 minutes,
6. Remove from heat, remove lid and let canner cool naturally for at least 15 minutes (it’s totally fine to let it cool completely before removing jars. If you need to use the canner again however, proceed with step 7)
7. Carefully remove jars from hot water using canning tongs
8. Place jars on a towel-lined surface away from drafts or activity, and cover with a second towel to insulate hot jars until they cool.