Slice the tops off the strawberries. Tip them all into a large, heavy-bottomed pan, cover with cold water and soak for 10 seconds before draining. This moistens the strawberries making the sugar easier to dissolve. Plus it makes sure they are completely clean.
Sprinkle over the sugar, add the star anise and lemon zest and juice. Toss it all together to coat then leave to sit for a few hours. The sugar has a hardening effect and will draw out the strawberries’ watery juices.
Meanwhile sterilise your jam jars and lids as detailed above. Place a saucer in the freezer.
Set the pan over medium heat to dissolve the sugar. Once no grains of sugar remain increase the heat to high and bring to the boil.
This jam is very quick so don’t wander off or start cooking dinner at the same time. Strawberry jam produces a lot of pale pink foam at the beginning so skim this away with a spoon to keep the finished product clear and sparkly.
Using a spatula stir the jam frequently as the fruit can easily catch and burn. Keep stirring and scraping the base of the pan but don’t reduce the heat otherwise it will darken. The bubbles will gradually become volcanic and spit.
Take the saucer out the freezer and spoon on a blob of jam. Chill for a couple of minutes then give it a poke to see if it wrinkles. If so turn off the heat and leave it to settle for five minutes so the fruit evenly disperses throughout the jam. If you want, remove the star anise.
Spoon the jam into the sterilised jars and tightly seal with a lid. Turn upside down for a few minutes to seal the vacuum. Leave to cool.