Put a few small plates in the freezer as you'll use them to test the marmalade later.
Using a vegetable peeler, remove the zest in strips from lemons. Cut strips into 1-by-1/8 inch strips. With a knife, cut off all white membrane, or pith, from peeled lemons. Discard the pith and membranes.
Working with one piece at a time, set fruit on its cut end and use a sharp knife to remove the white pith from the outside. Be as precise as possible—you really don't want any of the pith left on the fruit, as it is terribly bitter. Discard the pith.
Hold the peeled fruit over large bowl to catch the juice and hold with one hand. Then use a sharp paring knife to cut out the sections, letting the sections drop into the bowl below. Pick out the seeds and set them aside. You'll actually use them later.
Once you've cut the sections out of the fruit, you'll be left with a handful of the membrane that separates the lemon sections. Over the bowl with squeeze out as the remaining juice into the bowl with the lemon sections. Discard the membranes. Again, do not throw the seeds away.
Fill a stock pot with 2 cups of water and bring to a boil over high heat. Once boiling, add the zest and continue boiling over high heat for 10 minutes. Drain the water from the saucepan, leaving the zest then fill the saucepan with 2 cups of water again. Place the stock pot over the stove over high heat and set the timer for 10 minutes. One last time drain the water from the saucepan, fill with 2 cups water, place over high heat and set the timer for 10 minutes. Drain one last time while leaving the zest.
Add the fruit juices, water and honey into the stock pot along with zest. Stir to dissolve the honey and bring everything to a boil, about 10 minutes.
While the lemon mixture is heating up, make the ‘pectin bag.’ Put the seeds in a double layer of cheesecloth. Lay a large layer of cheesecloth in a medium bowl or plate and add the membranes and seeds on top. Tie the ends of the cheesecloth together so the seeds are held inside. You’re essentially making a teabag out of the cheesecloth or a ‘pectin bag.’
Once the lemon mixture starts to boil, add the "pectin bag" to the mix. Let cook for about 45 minutes to 1 hour, stirring occasionally.
For the final marmalade to set, it needs to be 220 F for at least 5 minutes. You can use a candy thermometer, but if you don't have one, you will need to do several tests using those frozen plates. If you’re not using a candy thermometer, make sure to watch it as it thickens. It’s easy to get distracted and forget about it on the stove.
After the marmalade has reached 220 F and stayed there for 5 minutes, you test the marmalade by dropping a spoonful of the mixture on one of the chilled plates you set in the freezer earlier. Let it sit for a minute, swirl the plate to spread the marmalade, then drag your finger through the mixture. If the marmalade is ready, it will leave a clean track behind it. The mixture will have also reduced and be thicker than water. When you hold your spoon up, you will notice that the liquid doesn’t roll off the spoon as quickly. You don’t want it to look super thicker and already like marmalade as it will continue to thicken as it cools. If it’s already super thick then it was end up hardening as it cools and won’t spread.
Once it’s finished cooking, remove the pectin bag from the marmalade. Use a large spoon to press the bag against the side of the pot to get as much of the marmalade out of the bag as possible. Discard the bag and its contents.
Remove the pot from the heat and let the marmalade mixture sit for about 5-10 minutes before transferring it to the jars. You’ll want it to cool slightly before transferring it to jars.