First cut and peel the watermelon. The easiest way I’ve found to peel half a watermelon is by cutting 1-1.5in (2.3-cm) thick circular discs away from the larger whole piece by piece. (see image below recipe for a visual) Once the slices are made, run the knife between the pink flesh and white rind all the way around the discs to remove the center of the watermelon. (set the watermelon centers aside to cut later or prep them now and refrigerate the pieces in a sealted container.) It’s okay if there is a little pink left on the rinds, it adds a subtle watermelon flavor to the pickled rinds. Next, use a y-peeler to strip away the green part of the rind from each ring. Once peeled, cut the rings into small strips. Fill your pickling container or containers with the fresh cut rind pieces. Then, set those aside and prepare the spices and the brine.

For the spice blend, measure out the tajín, black pepper, and mustard seeds into a single container and mix them. Set the blend aside.

Next, fill a small sauce pot with the vinegar and sugar and bring the solution to a boil. Once all of the sugar has dissolved, remove the liquid from the heat and pour it into the watermelon rind-filled container(s) until the liquid can cover the contents. (If the containers are not heat proof, wait for the liquid to cool a bit before pouring.) Next, split the spice blend evenly, according to the number of containers used. Seal the container(s) and give it(them) a shake to distribute the spices throughout the brine.

Let the container(s) cool on the counter until everything is room temperature. Then, place the watermelon rinds into the refrigerator at least overnight (preferrably 24hrs). Once, the rinds have chilled, open and enjoy.