Wash, clean and slice the lemons as shown. Remove the seeds and white membranes as much as you can.
Add them to the saucepan along with the water and let them cook over medium heat for about 20-25 minutes or until the lemons have softened.
Next, add in the sugar and continue cooking for about 30 minutes or until the temperature reads about 220 degrees on a candy thermometer.
Take this off heat, allow it to cool down and then store in glass jars or airtight containers.
Notes
Sugar tends to foam a lot when it cooks, so make sure you use a large saucepan for this recipe, or you'll risk it boiling over.
Make sure you use a clean, dry saucepan for this recipe. Also sterilize the lids and jars before you pour in the jam.
You're going to be adding the lemon peel in the marmalade too, so make sure you scrub and clean your lemons thoroughly before using them for this recipe.
Remember to cook until the peels have softened, and then add in the sugar. This is essential. Once you add in the sugar, the peels will no longer soften.
Choose your lemons carefully. If you spot any dark spots, softness or bruising on their surface, don't use them, as they can cause the marmalade to spoil.