In a Kilner jam pan, simmer the strawberries until hot.
Add the sugar and lemon juice and stir over a low heat until the sugar has dissolved using a Kilner wooden spatula.
Raise the heat and boil rapidly until the setting point is reached (104°C) on your Kilner jam thermometer.
Whilst hot, spoon the jam into hot sterilised Kilner jars, using a jam funnel and then seal.
Recipe courtesy of Kilner