Place chopped strawberries in a pot and bring to the boil.
Take care they don’t catch on the bottom of the pot.
Add sugar and stir until dissolved.
Bring to the boil, then boil for 15-20 minutes.
Stir regularly to ensure the jam doesn’t burn on the bottom of the pot.
At the end of cooking, add lemon juice (2 tablespoons to 700 grams of fruit and sugar).
Heat oven to 100 degrees and place clean jars in oven for 15 minutes.
Pour jam carefully into the heated, sterilised jars. I use a ladle.
Fix lids on firmly. When the lids pop down you know the jars are sealed.