Wash and de-seed loquats. Cut them into quarters. Add lemon juice to prevent them from browning (but also necessary for the jam to thicken).
Put the loquats, sugar and lemon in a large pot over high heat, stirring until the sugar melts.
Cut the vanilla bean in half and add to the loquat mixture.
Bring to a boil while stirring constantly, then reduce to a low simmer.
Stir frequently to prevent from burning. The fruit will start to break down. You will need to cook this for approx 1 hour.
At the 30 minute mark, remove the vanilla beans from the jam. Take a stick blender or immersion blender and blend the loquats. I like to leave some texture and lumps in my jam. Add the vanilla beans again and continue to cook for the hour time frame, until the jam is thick. I find that after blending, the jam can burn quicker, so remember to stir.
Ladle into jars and seal with a lid. Allow to cool and set. Keep refrigerated unless you have properly canned and sealed the jam. Enjoy.