In a medium saucepan, combine cranberries, 1/4 cup sugar, orange zest and orange juice; bring to a boil over medium-high heat. Boil, stirring occasionally, for 15 to 20 minutes or until cranberries have all popped (you can help them along by smushing them against the pot with the back of the spoon). Taste and add more sugar if you wish, then cool. Makes about 1 cup.