1-To prepare the radishes, slice off the: To prepare the radishes, slice off the green tops and bottoms, scrub them clean, then use a sharp chef’s knife or mandolin to slice them into very thin rounds.
2-Pack the rounds into a pint-sized canning: Pack the rounds into a pint-sized canning jar. Top with the mustard seeds, red pepper flakes, peppercorns, and garlic.
3-In a small saucepan, combine the apple: In a small saucepan, combine the apple cider vinegar, water, sugar, and salt. Bring mixture to a boil and whisk until sugar is dissolved, about 30-60 seconds.
4-Pour the hot mixture over the sliced: Pour the hot mixture over the sliced radishes, making sure they’re submerged in the liquid. Fasten the lid.
5-Set aside to cool to room temperature: Set aside to cool to room temperature (about 1 hour), then transfer to the refrigerator. Enjoy the next day for best flavor.