Add sugar and water to a large saucepan, heat over medium-high heat, stirring often until boiling. Boil until sugar completely dissolves, about 5 minutes.
Lower heat to medium, then gently stir in cranberries.
Heat until boiling, then reduce heat and simmer for 13-15 minutes stirring occasionally until cranberries burst.
Remove from heat and pour into a container and cool in the fridge for 2 hours or until chilled.
Notes
This cranberry sauce will keep in the fridge for up to 4 days.