Step by step recipe:

1. 5 min.
   Collect up all your fallen apples. It doesn't matter if they are still green, bruised or have been attacked by little creatures - rescue whatever you can!
2. 2 min.
   Rinse them briefly.
3. 5 min.
   Cut into quarters and discard any bad parts.
   
   You may well have plenty to reject and the apples will turn brown rapidly. This is quite normal.
4. 15 min.
   Put all the apple pieces through a centrifugal juicer. You will need 900g of juice to make 1.5 kg (just over 3 and a quarter pounds) of jelly, to which you will add the juice of 1 lemon.
   
   Skim off all the froth carefully, then leave the juice in the fridge for about 30 minutes to settle. You will see that a deposit has formed at top and another at the bottom.
5. 2 min.
   Discard the top deposit and pour the juice into a large saucepan, stopping before you get to the deposit at the bottom. Discard this as well.
6. 2 min.
   Mix 100 g granulated sugar and 50 g jam gelling agent in a bowl, using a whisk.
7. 2 min.
   Sieve 500 g granulated sugar into another bowl.
8. 5 min.
   Bring the apple juice to the boil.
9. 1 min.
   Tip in the sugar+setting agent mixture in one go.
10. 3 min.
    Bring back to the boil, whisking gently.
11. 1 min.
    Add 500 g granulated sugar all at once.
12. 7 min.
    Bring back to the boil, whisking gently, then leave to boil for 2 minutes.
13. 2 min.
    Pour the jelly into jars (still liquid at this stage).
14. 2 min.
    Screw on the lids.
15. 2 min.
    Turn the jars upside down so that the trapped air passes through the scalding hot jelly, which will sterilize it the simplest way.
16. 2 min.
    Stand the jars right way up and leave to cool.
17. 
    You can now enjoy your delicious apple jelly.