Method

Reserve 1/2 a lime per jar if you like bits in you marmalade, with the rest place in thick bottomed saucepan or a Maslin pan (best) cover with water & simmer for about 2 hours to go soft, remove from the pan & tip away the water then allow limes s to go cool enough to handle, slice each lime in the pan to catch the juice & remove the pips as you go, when all done blitz the pulp either with a stick/hand blender or in a food processor or liquidiser (best) to a smooth paste.

Pre-heat fan oven to 160'c to sterilise jars, wash the jars first in warm soppy water, rinse under the tap then place in a baking tray & put in the over for 10 mins to heat & dry, the lids & any rubber parts place in a saucepan with boiling water for a 2 to 3 mins before use.

Place sugar in the pan with the lime pulp back on a high heat & bring to the boil stirring, then turn down the heat to a low rolling boil stirring all the time for about 15 mins, it needs to get to the setting point which is 105'c use a electronic kitchen thermometer, you can also test using a very cold plate from the freezer, place a spoonful on the plate, when jam is cold push with you finger & if it is thick & wrinkles its done.

As soon as the jam is cooked take off the heat & let it settle for 1 min, then remove any scum from the top with a slotted spoon, cut & slice the reserved limes into shreds & add them & stir in, the residual heat will cook them, allow to thick for 20 mins stir again before putting into jars so the shred don't sink of float to the top.

Place hot jars from the oven on a baking tray on the worktop & fill to 1 cm from the top of the jar with a jam funnel, then place on the sterile lid, & set aside to cool.