01 -
Prepare 6 small jars (about 7oz/200ml each) with lids by washing thoroughly and placing them in an oven at 195°F (90°C) for 30 minutes to sterilize. Let them cool before using.
02 -
Wash the strawberries, remove the stems, and let them drain in a colander. Transfer to a tall, heavy-bottomed pot and crush them using an immersion blender or potato masher until you have a chunky puree.
03 -
Add the lemon juice and jam sugar to the strawberries and stir to combine. Bring the mixture to a rolling boil over medium-high heat while stirring constantly. Continue boiling for at least 3 minutes, stirring the whole time to prevent scorching.
04 -
Carefully ladle the hot jam into your prepared jars, filling them to within 1/8 inch (4mm) of the top. Wipe the rims clean, seal with lids, and turn upside down for 5-10 minutes (this helps create a vacuum seal). Turn right-side up and let cool completely.