Heat a medium saucepan on medium high heat. Add sugar, orange zest, orange juice and water. Whisk until dissolved about 1-2 minutes.
Add in the cranberries and cinnamon stick and stir, cook until cranberries start to pop about 10 minutes.
Reduce heat and stir in Grand Marnier, Simmer another 3-4 minutes.
Remove cinnamon sticks and use an immersion blender to blend the chunks out if desired.
Remove from heat and place in a serving bowl. Cranberry sauce will thicken as it cools.