Place strawberries, lemon juice and sugar in a large saucepan, over medium heat bring to the boil.
Wash jars in hot soapy water or in the dishwasher. Place a small plate in the freezer to later test the jam.
Simmer the jam for 40-50 minutes checking after 40 minutes to see if setting point has been reached.
To test if setting point has been reached place a teaspoon of jam on the plate from the freezer, it will set within 30-60 seconds if it is ready.
Place the jars on a tray and put in a low oven to dry and sterilize for 10 minutes or so, make sure to pour the jam into the jars while they are still warm. This is important so the jars don't break when you pour the hot jam into them.
I find it easier to pour the jam into the jars by using a jug, be very careful it is very hot, place the lids on the jars and set aside to cool.
Thermomix Instructions
Place strawberries, sugar and lemon juice in the Thermomix bowl, mix 15 Seconds/Speed 5.
Cook 40-50 minutes/Varoma/Speed 1, testing for setting point after 40 minutes, continue cooking until setting point is reached.
Pour jam into jars, set aside to cool.
Notes
I use this recipe for most of my jams.You can use regular white sugar if you prefer, but I use the Jam Sugar to help with the setting quality.You can use frozen fruit but let it sit out on the bench for 30 minutes or so before using, you may need to cook for a little longer though, just test in 5 minute intervals after that initial 40-50 minutes.