This recipe is part of our healthy soul food menu.
Prepare the watermelon rinds by removing the green skin with a peeler or utility knife. Cut away most of the red flesh with a knife, but leave a thin coat. Cut as much of the rind as possible into 1/2-inch cubes (many of the pieces will be odd shapes) until you generate 10 cups of rind. Set aside.
In a large stockpot over medium-low heat, make a brine by combining 3 quarts (12 cups) water with 1/4 cup sugar, salt, 2 cinnamon sticks, and 1 tablespoon cloves. Stir well until the sugar and salt are completely dissolved. Remove from heat and cool. Transfer watermelon rind to the brine. Place a small plate on top of the rinds to ensure that they are completely covered in water and don't float to the top. Soak overnight.
Drain the rinds and rinse several times with cold water.
Combine the rinds with enough cold water to just cover them in a stockpot. Bring to a boil, lower heat to medium, then simmer until the pieces are tender but still crisp, about 10 minutes. Drain and set aside.
Combine orange and lemon slices, vinegars, and remaining sugar, cinnamon sticks, and cloves with 3 cups water in stockpot. Bring to a boil over high heat. Add the rinds, bring back to a boil, reduce heat to low, cover, and simmer for 10 minutes.
Drain the rinds, catching the liquid in a bowl, and set them aside. Add the liquid back to the stockpot, bring to a boil over high heat, and reduce until it thickens slightly, 12 to 15 minutes. Transfer syrup to a metal bowl; let cool.
Place syrup and rinds in a plastic covered container; store in the refrigerator for up to 2 weeks.
This recipe was adapted from Vegan Soul Kitchen, by Bryant Terry (Da Capo).