Choose the ripest strawberries and wash them well. Remove the stems, chop them into little pieces and put them in a bowl.
Carefully peel the lemon and add the peel to the strawberries. Squeeze the lemon and add the juice to the strawberries. Stir in sugar. Leave the mixture in the fridge for a day.
Remove the peel and pour the strawberry mixture in a large pot. Bring to the boil over low heat; simmer for 20 minutes or so, skimming off any foam that comes to the top. The sugar will start to caramelise and the strawberries will become mushy. Continue stirring until you have a mixture that has the colour and consistency of jam. Taste to see if it is sweet enough, adding more sugar if necessary.
Once the jam is ready, pour it into clean, warm glass jars; cover and cool.
I made this jam yesterday exactly as the receipe stated. The jam wouldn't thicken so I boiled it for about 20 minutes, it still wasn't thick but I bottled it and it did thicken up when cold. Unfortunately it is far too sweet, I would think that half the sugar would be sufficient. - 15 Apr 2013