Instructions

• Wash the orange and the lemon well.
• Slice the orange, the lemon, and the 2 or 3 slices of fresh ginger.
• Place the fruit and ginger slices into a medium pot with 5 cups water.
• Bring the pot to a boil, then reduce heat and simmer for 30 minutes.
• Place a sieve over a bowl and pour the pot contents through the sieve to strain the liquid. Press the fruit and ginger in the sieve to extract as much liquid as possible; discard the solids.
• Return the strained liquid to the pot.
• Add 1 cup sugar, 1/2 cup vinegar, 1 cup ketchup, and a few drops of red food coloring if using.
• Whisk the mixture until the sugar is dissolved and the ingredients are well blended.
• Heat the sauce over medium-high heat until it starts to warm through.
• In a small bowl, combine 3 tablespoons cornstarch and 3 tablespoons water; stir until smooth to make a slurry.
• With the sauce stirring constantly, slowly stream in the cornstarch slurry. Continue stirring until the sauce thickens.
• When the sauce has thickened to your desired consistency, remove it from the heat.