Slice oranges and lemons, discard any seeds. Put in a saucepan and add water. Bring to a boil. Remove from heat and stir in the sugar. Let it sit overnight.

The next day bring the mixture to simmer on low heat for about two hours uncovered. Using a candy thermometer make sure the jam records 220°F. At this point the jam should be viscous, not too runny or too thick. Laddle into hot mason jars and close tight. Store for a year.