Place 2 saucers or small plates in the freezer, ready to check for the setting point of your marmalade.
Thoroughly wash the lemons. Remove each end of the lemons and cut the lemons into quarters lengthways. Holding two of the quarters together, slice as thinly as possible and remove any seeds.
Place the lemon slices in a non-reactive bowl. See Note 3. Add 6 cups of water, cover the bowl and leave the lemons to stand overnight.
The following day, drain the lemons and water into a large, non-reactive saucepan. – See Note 4.
Over medium-high heat, bring the fruit and water to the boil. Boil for approximately 15 minutes or until the lemon peel is tender, stirring occasionally with a long-handled wooden spoon. – See Note 5. The time may vary slightly depending on the variety of lemon and the thickness of the slices.
Add the sugar and stir well to dissolve it. After dissolving the sugar, return the fruit to the boil, stir occasionally and skim to remove any foam. Continue to stir until the marmalade reaches setting point, about 20 minutes. – See Note 6
To test for setting point, I use the “wrinkle” test. Take one of your saucers from the freezer and pour a small amount of marmalade onto it. Let it cool for a minute then push against the marmalade with the tip of your finger. If the surface wrinkles it means setting point has been reached.
Take the mixture off the heat and let the marmalade stand for about 10 minutes. This will help evenly distribute the fruit throughout the jars.
Remove your jars from the oven and carefully ladle the marmalade into the heated, sterilised jars. You need to be very careful. Splashing yourself with hot marmalade will result in a very serious burn. I suggest you have clothing with long sleeves and ensure that you do not have children nearby.