Quick pickled radishes - 10 minutes! These add a great tart zing and satisfying crunch to tacos (love them on fish tacos), salads, or sandwiches.
Slice a bunch of radishes thin (on a mandoline, the thinnest setting) and pack into a pint-sized mason jar.
Put a 1/2 tsp of whole mustard seeds and 1/4 to 1/2 tsp of red pepper flakes (depending on how spicy you want them) on top of the radishes.
Pour 3/4 cup of water and 3/4 cup of vinegar (apple cider, white wine vinegar, or regular white vinegar all work) into a pot. Add 3 tbsp sugar and 2 tsp salt. Bring to a boil; whisk occasionally until sugar and salt is mixed in.
Carefully pour mixture over radishes.
Allow to cool to room temperature before closing mason jar or refrigerating radishes.
Enjoy right away and up to 3 weeks.