This syrup can be poured over French toast or pancakes as an alternative to maple syrup.
Combine the sugar and 1/2 cup water in a small saucepan. Bring to a boil; stir until sugar has dissolved. Combine juice and cornstarch in a bowl; pour into sugar syrup. Simmer gently until thick, 6 to 8 minutes. Add butter; stir until it melts. Serve warm.