cut plums in little pieces

mix plums with sugars and lemon juice

set aside for at least 1 hour

add cinnamon and bring the mix to boil at medium/low heat

when it begins to boil lower the heat and let cook for 20 minutes stirring occasionally

test the tickness putting a teaspoon of the mix in a cold plate and waiting 1 minute. If it remains liquid let cook 5 minutes more then recheck

beware not to do it too tick!

let it cool in glass jar and put in the fridge to you consume it in a pair of weeks

if you want, pasteourizate the jars to preserve the jam up to one year