Chop kiwi into small pieces. Transfer chopped kiwi, sugar, and lemon juice to a pan.
Cover and cook kiwi for 15 minutes on medium-low heat until the color of kiwi changes completely and the kiwi turns soft and mushy.
Remove lid and when jam turns glossy, blend jam with an immersion blender. Just 2-3 whizz to break the flesh. If kiwi is very soft you can also mash it with a potato masher.
Continue to cook for 10 minutes until the jam reaches the setting point. Keep stirring at intervals and reduce heat towards the end.
To test consistency, do a cold plate test by putting a large drop of jam on a cold plate. Wait for 30 secs to cool. Kiwi Jam should hold its shape on the plate without spreading like water. If the jam is not set continue to cook for another 5 mins. And if it is set then stop cooking. Jam is ready.
Then ladle the hot jam to clean dry jars keeping only ½ inch space between lid and jam. Place the lid and turn the jar upside down to create a vacuum seal. Store jam in the fridge or freezer.