Remove the green stalks and leaves and halve them lengthways
Zest one lemon and set aside. Juice it after you've zested it.
Place the strawberries in a bowl and add the sugar and lemon juice.Thoroughly mix the fruit, sugar and lemon juice.
Cover and let it sit for 1 hour at room temperature.
Place the strawberries into a large pot or pan and bring them to a rolling steady boil.Some foam will rise to the top. You can skim this off if you want but it's optional. If you plan on canning it, it helps to remove the foam so the free headspace needed is accurate.
Stir the mix often and keep watching it so that it doesn't catch or burn.
Measure the doneness by preferably using a temperature probe. It should reach a temperature of 104°C or 220°F. Alternatively, place a bit of jam on a plate, place it in the freezer for 10 minutes and if you draw a line through it, it should stay put. When it's done you should can it or move it to the fridge.
You should give the jam a good 12 hours to completely cool down and set before serving.
Video
Notes
To make this recipe with pectin add 12 grams or 1 tablespoon of pectin with the sugar and mix it well. Follow the rest of the steps as stated. This will give you a completely set strawberry jam.
See post for variations and alternative flavours.
See post for canning instructions.
Best stored in the fridge.
If not canned or vacuum-sealed it will last for up to 2 weeks.