1 Kg of clean, organic, unwaxed lemons
1/2Kg sugar
1)Wash lemons well ,cut off the stem entirely without puncturing lemon, then place in a large sauce pan with straight tall sides.Fill with about 5 -7 cups water to just cover lemons.Simmer these whole lemons gently until the skins become incredibly soft and a fork slips through easily—about 2 hours if large, 1 hour if they are small and the skins fine.
2)Remove the lemons from the pot, saving the water left in the pan and topping up, if necessary, to have about 2.5 cups of liquid.
3)Using a food mill, cut the lemons in quarters and pass through a food mill set over a bowl to collect the pulp. The seeds and some hard membranes will be separated from the pulp and can be discarded. If no food mill, scoop out contents of lemon and set aside soft peels. Add contents to a bowl and separate seeds. then blend the contents including skins in blender, processor or strainer.
4)Add water, sugar and pulp to pot .Bring the marmalade to a boil and boil rapidly for about 20 minutes for a soft set. The liquid will first look very opaque and a little frothy, then as it cooks, it will turn transparent golden and shiny. watch and stir to keep froth from boiling over
5)To test, put a saucer in freezer once you start boiling. After 20 minutes ladel some marmalade to cold sacucer and return to freezer for 30 seconds and then remove. Turn and slightly tilt saucer. If surface crinkles you have a nice soft set. If you want a harder set return to boil for a few more minutes
6) Add to jars and refrigerate after cooling. If you intend to store in pantry follow proper canning technique: https://nchfp.uga.edu/how/can_07/citrus_marmalade.html
Based on recipe from food 52 recipe: https://food52.com/recipes/66985-lemon-marmalade-marmellata-di-limoni
This exact methodology and ingredient preoprtions can be used to make kumquat marmalade . Simply replace lemons with kumquats