Chop the strawberries and place in a pan along with the lemon juice and sugar, and bring to a low heat and stir for the first 3 minutes... Leave on low heat for 20 minutes, always looking and stirring if necessary. Until it's at the point of jelly.
Once it's ready, add the jam in a small pot and put it in the fridge. And that's it, you can eat it with bread, toast, cheese and etc...