Step 1

Wipe the strawberries with a damp cloth to remove any dirt. Hull and halve, or quarter if large. Tumble into a large bowl and stir through half the sugar, coating the fruit well. Leave them to macerate for a couple of hours.

Step 2

Transfer to a preserving pan or very large high-sided saucepan, scraping out the bowl thoroughly. Add the rest of the sugar and the lemon juice. Put a couple of saucers in the freezer (unless you have a sugar thermometer). Cook slowly over a low heat until the sugar has dissolved, then bring to the boil and bubble rapidly for about 20 minutes or until the setting point is reached (see next step).

Step 3

To test whether the setting point has been reached, take the pan off the heat and either use a sugar thermometer (once it gets to 105°C it’s ready) or spoon a little of the jam onto a cold saucer from the freezer. Return the saucer to the freezer for a minute to cool the jam, then push it with the tip of your finger – if the jam wrinkles on the surface, the setting point has been reached. If it hasn’t set, continue boiling for a couple more minutes, then repeat the test.

Step 4

Remove any scum from the surface of the jam with a metal spoon and leave to sit for 10 minutes so the strawberries are well distributed throughout the jam. Spoon into warm, freshly sterilised jars, to within 3mm from the top. Top with a waxed disc and seal with a lid, then leave to cool.