Mix the sugar and the juice in a pot, and place on a low heat until the sugar dissolves
Add the cranberries, zest, sherry and thyme. Bring to a quick boil and then reduce heat to let simmer. The berries will eventually 'pop' releasing their juice.
After about 10min, take off the heat and cool. The sauce will thicken as it cools. Store in a covered container, then unveil to wow your family.