1. Prepare the jars

    Preheat the oven to gas 1, 140°C, fan 120°C. Sterilise 4 x 350ml jam jars and lids by lowering them into a pan of boiling water; leave for 1-2 minutes. Using tongs, carefully lift out. Place the jars in the oven to dry. Once completely dry, remove and set to one side to cool.

    Put 2 saucers in the freezer (for testing the consistency of the jam). Cut out 4 circles of greaseproof paper to fit the jar tops and set aside until needed.

  2. Soften the berries

    Hull and halve (or quarter if large) 1.2kg strawberries, and then layer in a non-metallic bowl with 800g jam sugar and the juice of 1 lemon. Mix well to combine, cover in clingfilm and leave for 2 hours to soften. Once the time is up, mash the berries a little to break into smaller pieces.

  3. Heat the berries

    Tip the berries into a heavy based pan and heat gently until the sugar has dissolved, taking care not to let the mixture boil. Once the sugar has dissolved completely (you’ll be able to tell because the liquid will turn glossy) boil hard for precisely 4 minutes (use a kitchen timer).

  4. Check the set

    Turn off the heat. Remove one of the saucers from the freezer. Put a small spoonful of jam onto it and leave to harden for 1-2 minutes. To test whether the jam has set, push the jam a little with your finger. If it’s ready, it should gather and wrinkle. If the jam separates and your finger runs through, boil it again for another 2 minutes and test again. If necessary, keep boiling and testing at 2 minutes increments until the jam wrinkles.

  5. Pour into jars

    Once the jam has reached a good setting point on the saucer, skim off any pink scum from the top, and while still hot, carefully pour into the sterilised jars using a ladle. Top immediately with a circle of greaseproof paper and then seal tightly with the lid.

  6. Enjoy

    Serve the jam with freshly made scones and clotted cream. Store in the fridge and use within 3 months.

    TescoOnline JamStepFinal

    Calories 35 (2%), sugar 9g (10%), fat 0.1g (0%), saturates 0g (0%), salt 0g (0%), based on a 1 tbsp serving.

  7. Ingredients

    We've made a handy shopping list so you can get everything you need to make this classic strawberry jam – it only uses three ingredients. Don't forget to screenshot before you go shopping!

    1.2kg strawberries
    800g jam sugar
    juice of 1 lemon