In a medium saucepan, combine the sugar, water, orange zest, and lemon juice. Bring to a simmer, stirring constantly until the sugar dissolves. Once the sugar dissolves, stop stirring, and continue to cook until the mixture thickens and turns golden, 10 to 15 minutes. Remove from the heat and add the orange juice (the mixture will bubble slightly). Return to medium-high heat and stirring constantly, cook for 1 minute.
Remove from the heat and cool slightly. Strain through a fine mesh strainer into a clean bowl and cool to room temperature before serving.
Yield: 1 3/4 cups